diff --git a/01-good-old-times/tf-01.py b/01-good-old-times/tf-01.py
index ecd0897..bd8caea 100755
--- a/01-good-old-times/tf-01.py
+++ b/01-good-old-times/tf-01.py
@@ -1,6 +1,4 @@
 #!/usr/bin/env python
-
-from __future__ import print_function
 import sys, os, string
 
 # Utility for handling the intermediate 'secondary memory'
diff --git a/02-go-forth/forth.py b/02-go-forth/forth.py
index 1ab978c..2fa1fc7 100755
--- a/02-go-forth/forth.py
+++ b/02-go-forth/forth.py
@@ -4,7 +4,6 @@
 #   Author: Chris Meyers @
 #           http://openbookproject.net/py4fun/forth/forth.html
 #
-from __future__ import print_function
 import re
 
 try:
diff --git a/02-go-forth/tf-02.py b/02-go-forth/tf-02.py
index 8b9682f..9b6f5bc 100755
--- a/02-go-forth/tf-02.py
+++ b/02-go-forth/tf-02.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-from __future__ import print_function
 import sys, re, operator, string
 
 #
@@ -92,7 +91,7 @@ def frequencies():
 
 def sort():
     # Not in style, left as exercise
-    stack.extend(sorted(stack.pop().iteritems(), key=operator.itemgetter(1)))
+    stack.extend(sorted(stack.pop().items(), key=operator.itemgetter(1)))
 
 # The main function
 #
diff --git a/03-monolith/tf-03.py b/03-monolith/tf-03.py
index 1ca09c9..def21d4 100755
--- a/03-monolith/tf-03.py
+++ b/03-monolith/tf-03.py
@@ -1,6 +1,4 @@
 #!/usr/bin/env python
-
-from __future__ import print_function
 import sys, string
 # the global list of [word, frequency] pairs
 word_freqs = []
diff --git a/04-cookbook/tf-04.py b/04-cookbook/tf-04.py
index 4c9a193..9a31d40 100755
--- a/04-cookbook/tf-04.py
+++ b/04-cookbook/tf-04.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-from __future__ import print_function
 import sys, string
 
 # The shared mutable data
diff --git a/05-pipeline/tf-05.py b/05-pipeline/tf-05.py
index f95e102..409c5d1 100755
--- a/05-pipeline/tf-05.py
+++ b/05-pipeline/tf-05.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-from __future__ import print_function
 import sys, re, operator, string
 
 #
@@ -59,7 +58,7 @@ def sort(word_freq):
     and returns a list of pairs where the entries are
     sorted by frequency 
     """
-    return sorted(word_freq.iteritems(), key=operator.itemgetter(1), reverse=True)
+    return sorted(word_freq.items(), key=operator.itemgetter(1), reverse=True)
 
 def print_all(word_freqs):
     """
diff --git a/06-code-golf/tf-06-1.py b/06-code-golf/tf-06-1.py
index 711c89d..cf417fd 100644
--- a/06-code-golf/tf-06-1.py
+++ b/06-code-golf/tf-06-1.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-from __future__ import print_function
 import re, string, sys
 
 stops = set(open("../stop_words.txt").read().split(",") + list(string.ascii_lowercase))
diff --git a/06-code-golf/tf-06-bm.py b/06-code-golf/tf-06-bm.py
index 34e8d50..27d9006 100644
--- a/06-code-golf/tf-06-bm.py
+++ b/06-code-golf/tf-06-bm.py
@@ -1,3 +1,2 @@
-from __future__ import print_function
 from functools import reduce
-print (reduce(lambda string, tup: string + tup[0] + ' - ' + str(tup[1]) + '\n', sorted( filter(lambda tup: tup[0] not in open(__import__('os').path.join(__import__('os').path.dirname(__file__), '..', 'stop_words.txt')).read().lower().split(','),  reduce(lambda word_dict, word: word_dict if (word_dict.__setitem__(word, word_dict.get(word, 0) + 1) if True else None) else word_dict, filter(lambda word: len(word) > 1, (''.join(map(lambda letter: ' ' if ord(letter) not in set(range(ord('a'), ord('z') + 1)) else letter, open(__import__('sys').argv[1]).read().lower()))).split()), {}).iteritems()), key=lambda tup: tup[1], reverse=True)[0:25], '')) # hole in one?
+print (reduce(lambda string, tup: string + tup[0] + ' - ' + str(tup[1]) + '\n', sorted( filter(lambda tup: tup[0] not in open(__import__('os').path.join(__import__('os').path.dirname(__file__), '..', 'stop_words.txt')).read().lower().split(','),  reduce(lambda word_dict, word: word_dict if (word_dict.__setitem__(word, word_dict.get(word, 0) + 1) if True else None) else word_dict, filter(lambda word: len(word) > 1, (''.join(map(lambda letter: ' ' if ord(letter) not in set(range(ord('a'), ord('z') + 1)) else letter, open(__import__('sys').argv[1]).read().lower()))).split()), {}).items()), key=lambda tup: tup[1], reverse=True)[0:25], '')) # hole in one?
diff --git a/06-code-golf/tf-06-pn.py b/06-code-golf/tf-06-pn.py
index 1df5e05..9da618f 100755
--- a/06-code-golf/tf-06-pn.py
+++ b/06-code-golf/tf-06-pn.py
@@ -1,8 +1,6 @@
 #!/usr/bin/env python
 # My golf score is slightly lower!  
 # Best wishes, Peter Norvig
-
-from __future__ import print_function
 import re, sys, collections
 
 stopwords = set(open('../stop_words.txt').read().split(','))
diff --git a/06-code-golf/tf-06.py b/06-code-golf/tf-06.py
index ad02820..8aedd14 100755
--- a/06-code-golf/tf-06.py
+++ b/06-code-golf/tf-06.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-from __future__ import print_function
 import heapq, re, sys
 
 words = re.findall("[a-z]{2,}", open(sys.argv[1]).read().lower())
diff --git a/07-infinite-mirror/tf-07.py b/07-infinite-mirror/tf-07.py
index 110ef72..68b750e 100755
--- a/07-infinite-mirror/tf-07.py
+++ b/07-infinite-mirror/tf-07.py
@@ -1,9 +1,8 @@
 #!/usr/bin/env python
-from __future__ import print_function
 import re, sys, operator
 
 # Mileage may vary. If this crashes, make it lower
-RECURSION_LIMIT = 9500
+RECURSION_LIMIT = 5000
 # We add a few more, because, contrary to the name,
 # this doesn't just rule recursion: it rules the 
 # depth of the call stack
@@ -35,11 +34,12 @@ def wf_print(wordfreq):
 
 stop_words = set(open('../stop_words.txt').read().split(','))
 words = re.findall('[a-z]{2,}', open(sys.argv[1]).read().lower())
+
 word_freqs = {}
 # Theoretically, we would just call count(words, stop_words, word_freqs)
 # Try doing that and see what happens.
 for i in range(0, len(words), RECURSION_LIMIT):
     count(words[i:i+RECURSION_LIMIT], stop_words, word_freqs)
 
-wf_print(sorted(word_freqs.iteritems(), key=operator.itemgetter(1), reverse=True)[:25])
+wf_print(sorted(word_freqs.items(), key=operator.itemgetter(1), reverse=True)[:25])
 
diff --git a/08-kick-forward/tf-08.py b/08-kick-forward/tf-08.py
index 8044f58..ecf1b53 100755
--- a/08-kick-forward/tf-08.py
+++ b/08-kick-forward/tf-08.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-from __future__ import print_function
 import sys, re, operator, string
 
 #
@@ -37,7 +36,7 @@ def frequencies(word_list, func):
     func(wf, print_text)
 
 def sort(wf, func):
-    func(sorted(wf.iteritems(), key=operator.itemgetter(1), reverse=True), no_op)
+    func(sorted(wf.items(), key=operator.itemgetter(1), reverse=True), no_op)
 
 def print_text(word_freqs, func):
     for (w, c) in word_freqs[0:25]:
diff --git a/09-the-one/tf-09.py b/09-the-one/tf-09.py
index eaf6deb..29f78c0 100755
--- a/09-the-one/tf-09.py
+++ b/09-the-one/tf-09.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-from __future__ import print_function
 import sys, re, operator, string
 
 #
@@ -51,7 +50,7 @@ def frequencies(word_list):
     return word_freqs
 
 def sort(word_freq):
-    return sorted(word_freq.iteritems(), key=operator.itemgetter(1), reverse=True)
+    return sorted(word_freq.items(), key=operator.itemgetter(1), reverse=True)
 
 def top25_freqs(word_freqs):
     top25 = ""
diff --git a/10-things/tf-10.py b/10-things/tf-10.py
index 2bb3544..631b505 100755
--- a/10-things/tf-10.py
+++ b/10-things/tf-10.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-from __future__ import print_function
 import sys, re, operator, string
 from abc import ABCMeta
 
@@ -56,7 +55,7 @@ class WordFrequencyManager(TFExercise):
             self._word_freqs[word] = 1
 
     def sorted(self):
-        return sorted(self._word_freqs.iteritems(), key=operator.itemgetter(1), reverse=True)
+        return sorted(self._word_freqs.items(), key=operator.itemgetter(1), reverse=True)
 
     def info(self):
         return super(WordFrequencyManager, self).info() + ": My major data structure is a " + self._word_freqs.__class__.__name__
diff --git a/11-letterbox/tf-11.py b/11-letterbox/tf-11.py
index e9f041c..56eb7d0 100755
--- a/11-letterbox/tf-11.py
+++ b/11-letterbox/tf-11.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-from __future__ import print_function
 import sys, re, operator, string
 
 class DataStorageManager():
@@ -64,7 +63,7 @@ class WordFrequencyManager():
             self._word_freqs[word] = 1
 
     def _sorted(self):
-        return sorted(self._word_freqs.iteritems(), key=operator.itemgetter(1), reverse=True)
+        return sorted(self._word_freqs.items(), key=operator.itemgetter(1), reverse=True)
 
 class WordFrequencyController():
 
diff --git a/12-closed-maps/tf-12.py b/12-closed-maps/tf-12.py
index 7e53560..56c9527 100644
--- a/12-closed-maps/tf-12.py
+++ b/12-closed-maps/tf-12.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-from __future__ import print_function
 import sys, re, operator, string
 
 # Auxiliary functions that can't be lambdas
@@ -35,7 +34,7 @@ stop_words_obj = {
 word_freqs_obj = {
     'freqs' : {},
     'increment_count' : lambda w : increment_count(word_freqs_obj, w),
-    'sorted' : lambda : sorted(word_freqs_obj['freqs'].iteritems(), key=operator.itemgetter(1), reverse=True)
+    'sorted' : lambda : sorted(word_freqs_obj['freqs'].items(), key=operator.itemgetter(1), reverse=True)
 }
 
 data_storage_obj['init'](sys.argv[1])
diff --git a/13-abstract-things/tf-13.py b/13-abstract-things/tf-13.py
index 41af3a7..6ca42f6 100755
--- a/13-abstract-things/tf-13.py
+++ b/13-abstract-things/tf-13.py
@@ -1,31 +1,27 @@
 #!/usr/bin/env python
-from __future__ import print_function
 import abc, sys, re, operator, string
 
 #
 # The abstract things
 #
-class IDataStorage (object):
+class IDataStorage (metaclass=abc.ABCMeta):
     """ Models the contents of the file """
-    __metaclass__ = abc.ABCMeta
 
     @abc.abstractmethod
     def words(self):
         """ Returns the words in storage """
         pass
 
-class IStopWordFilter (object):
+class IStopWordFilter (metaclass=abc.ABCMeta):
     """ Models the stop word filter """
-    __metaclass__ = abc.ABCMeta
 
     @abc.abstractmethod
     def is_stop_word(self, word):
         """ Checks whether the given word is a stop word """
         pass
 
-class IWordFrequencyCounter(object):
+class IWordFrequencyCounter(metaclass=abc.ABCMeta):
     """ Keeps the word frequency data """
-    __metaclass__ = abc.ABCMeta
 
     @abc.abstractmethod
     def increment_count(self, word):
@@ -72,15 +68,15 @@ class WordFrequencyManager:
             self._word_freqs[word] = 1
 
     def sorted(self):
-        return sorted(self._word_freqs.iteritems(), key=operator.itemgetter(1), reverse=True)
+        return sorted(self._word_freqs.items(), key=operator.itemgetter(1), reverse=True)
 
 
 #
 # The wiring between abstract things and concrete things
 #
-IDataStorage.register(DataStorageManager)
-IStopWordFilter.register(StopWordManager)
-IWordFrequencyCounter.register(WordFrequencyManager)
+IDataStorage.register(subclass=DataStorageManager)
+IStopWordFilter.register(subclass=StopWordManager)
+IWordFrequencyCounter.register(subclass=WordFrequencyManager)
 
 #
 # The application object
diff --git a/14-hollywood/tf-14.py b/14-hollywood/tf-14.py
index 551a937..3a579ae 100755
--- a/14-hollywood/tf-14.py
+++ b/14-hollywood/tf-14.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-from __future__ import print_function
 import sys, re, operator, string
 
 #
@@ -88,7 +87,7 @@ class WordFrequencyCounter:
             self._word_freqs[word] = 1
 
     def __print_freqs(self):
-        word_freqs = sorted(self._word_freqs.iteritems(), key=operator.itemgetter(1), reverse=True)
+        word_freqs = sorted(self._word_freqs.items(), key=operator.itemgetter(1), reverse=True)
         for (w, c) in word_freqs[0:25]:
             print(w, ' - ', c)
 
diff --git a/15-bulletin-board/tf-15.py b/15-bulletin-board/tf-15.py
index 4327f73..52061b9 100755
--- a/15-bulletin-board/tf-15.py
+++ b/15-bulletin-board/tf-15.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-from __future__ import print_function
 import sys, re, operator, string
 
 #
@@ -78,7 +77,7 @@ class WordFrequencyCounter:
             self._word_freqs[word] = 1
 
     def print_freqs(self, event):
-        word_freqs = sorted(self._word_freqs.iteritems(), key=operator.itemgetter(1), reverse=True)
+        word_freqs = sorted(self._word_freqs.items(), key=operator.itemgetter(1), reverse=True)
         for (w, c) in word_freqs[0:25]:
             print(w, ' - ', c)
 
diff --git a/16-introspective/tf-16.py b/16-introspective/tf-16.py
index 5c9659a..7d54faf 100755
--- a/16-introspective/tf-16.py
+++ b/16-introspective/tf-16.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-from __future__ import print_function
 import sys, re, operator, string, inspect
 
 def read_stop_words():
@@ -35,7 +34,7 @@ def frequencies(word_list):
 
 def sort(word_freq):
     # Meta-level data: locals()
-    return sorted(locals()['word_freq'].iteritems(), key=operator.itemgetter(1), reverse=True)
+    return sorted(locals()['word_freq'].items(), key=operator.itemgetter(1), reverse=True)
 
 def main():
     word_freqs = sort(frequencies(extract_words(sys.argv[1])))
diff --git a/17-reflective/tf-17.py b/17-reflective/tf-17.py
index 8495ed6..1abd4c0 100755
--- a/17-reflective/tf-17.py
+++ b/17-reflective/tf-17.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-from __future__ import print_function
 import sys, re, operator, string, os
 
 #
@@ -22,7 +21,7 @@ def frequencies_imp(word_list):
 if len(sys.argv) > 1:
     extract_words_func = "lambda name : [x.lower() for x in re.split('[^a-zA-Z]+', open(name).read()) if len(x) > 0 and x.lower() not in stops]"
     frequencies_func = "lambda wl : frequencies_imp(wl)"
-    sort_func = "lambda word_freq: sorted(word_freq.iteritems(), key=operator.itemgetter(1), reverse=True)"
+    sort_func = "lambda word_freq: sorted(word_freq.items(), key=operator.itemgetter(1), reverse=True)"
     filename = sys.argv[1]
 else:
     extract_words_func = "lambda x: []"
diff --git a/18-aspects/tf-18.py b/18-aspects/tf-18.py
index b4f0006..b3a22b9 100755
--- a/18-aspects/tf-18.py
+++ b/18-aspects/tf-18.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-from __future__ import print_function
 import sys, re, operator, string, time
 
 #
@@ -25,7 +24,7 @@ def frequencies(word_list):
     return word_freqs
 
 def sort(word_freq):
-    return sorted(word_freq.iteritems(), key=operator.itemgetter(1), reverse=True)
+    return sorted(word_freq.items(), key=operator.itemgetter(1), reverse=True)
 
 # The side functionality
 def profile(f):
diff --git a/19-plugins/plugins-src/frequencies1.py b/19-plugins/plugins-src/frequencies1.py
index 935b2ed..7a5cb65 100644
--- a/19-plugins/plugins-src/frequencies1.py
+++ b/19-plugins/plugins-src/frequencies1.py
@@ -7,5 +7,5 @@ def top25(word_list):
             word_freqs[w] += 1
         else:
             word_freqs[w] = 1
-    return sorted(word_freqs.iteritems(), key=operator.itemgetter(1), reverse=True)[:25]
+    return sorted(word_freqs.items(), key=operator.itemgetter(1), reverse=True)[:25]
 
diff --git a/19-plugins/plugins/frequencies1.pyc b/19-plugins/plugins/frequencies1.pyc
index a204d1f..9e95fee 100644
Binary files a/19-plugins/plugins/frequencies1.pyc and b/19-plugins/plugins/frequencies1.pyc differ
diff --git a/19-plugins/plugins/frequencies2.pyc b/19-plugins/plugins/frequencies2.pyc
index 30e5286..f712034 100644
Binary files a/19-plugins/plugins/frequencies2.pyc and b/19-plugins/plugins/frequencies2.pyc differ
diff --git a/19-plugins/plugins/words1.pyc b/19-plugins/plugins/words1.pyc
index cae656d..f574711 100644
Binary files a/19-plugins/plugins/words1.pyc and b/19-plugins/plugins/words1.pyc differ
diff --git a/19-plugins/plugins/words2.pyc b/19-plugins/plugins/words2.pyc
index 699a7e5..7df3cf5 100644
Binary files a/19-plugins/plugins/words2.pyc and b/19-plugins/plugins/words2.pyc differ
diff --git a/19-plugins/tf-19.py b/19-plugins/tf-19.py
index e94096d..b7cf0cf 100755
--- a/19-plugins/tf-19.py
+++ b/19-plugins/tf-19.py
@@ -1,15 +1,16 @@
 #!/usr/bin/env python
-from __future__ import print_function
-import sys, ConfigParser, imp
+import sys, configparser, importlib.machinery
 
 def load_plugins():
-    config = ConfigParser.ConfigParser()
+    config = configparser.ConfigParser()
     config.read("config.ini")
     words_plugin = config.get("Plugins", "words")
     frequencies_plugin = config.get("Plugins", "frequencies")
     global tfwords, tffreqs
-    tfwords = imp.load_compiled('tfwords', words_plugin)
-    tffreqs = imp.load_compiled('tffreqs', frequencies_plugin)
+#    tfwords = importlib.load_compiled('tfwords', words_plugin)
+#    tffreqs = importlib.load_compiled('tffreqs', frequencies_plugin)
+    tfwords = importlib.machinery.SourcelessFileLoader('tfwords', words_plugin).load_module()
+    tffreqs = importlib.machinery.SourcelessFileLoader('tffreqs', frequencies_plugin).load_module()
 
 load_plugins()
 word_freqs = tffreqs.top25(tfwords.extract_words(sys.argv[1]))
diff --git a/20-constructivist/tf-20.py b/20-constructivist/tf-20.py
index b3c727a..0f74c05 100755
--- a/20-constructivist/tf-20.py
+++ b/20-constructivist/tf-20.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-from __future__ import print_function
 import sys, re, operator, string, inspect
 
 #
@@ -50,7 +49,7 @@ def sort(word_freq):
     if type(word_freq) is not dict or word_freq == {}:
         return []
 
-    return sorted(word_freq.iteritems(), key=operator.itemgetter(1), reverse=True)
+    return sorted(word_freq.items(), key=operator.itemgetter(1), reverse=True)
 
 #
 # The main function
diff --git a/21-tantrum/tf-21.py b/21-tantrum/tf-21.py
index b649656..9b925b3 100755
--- a/21-tantrum/tf-21.py
+++ b/21-tantrum/tf-21.py
@@ -1,6 +1,4 @@
 #!/usr/bin/env python
-
-from __future__ import print_function
 import sys, re, operator, string, traceback
 
 #
@@ -51,9 +49,9 @@ def sort(word_freq):
     assert(word_freq != {}), "I need a non-empty dictionary!"
 
     try:
-        return sorted(word_freq.iteritems(), key=operator.itemgetter(1), reverse=True)
+        return sorted(word_freq.items(), key=operator.itemgetter(1), reverse=True)
     except Exception as e:
-        print("Sorted threw {0}: {1}".format(e))
+        print("Sorted threw {0}".format(e))
         raise e
 
 #
diff --git a/22-passive-aggressive/tf-22.py b/22-passive-aggressive/tf-22.py
index ac2bd04..fa28130 100644
--- a/22-passive-aggressive/tf-22.py
+++ b/22-passive-aggressive/tf-22.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-from __future__ import print_function
 import sys, re, operator, string
 
 #
@@ -40,7 +39,7 @@ def sort(word_freqs):
     assert(type(word_freqs) is dict), "I need a dictionary! I quit!"
     assert(word_freqs != {}), "I need a non-empty dictionary! I quit!"
 
-    return sorted(word_freqs.iteritems(), key=operator.itemgetter(1), reverse=True)
+    return sorted(word_freqs.items(), key=operator.itemgetter(1), reverse=True)
 
 #
 # The main function
diff --git a/22-passive-aggressive/tf-23-monadic.py b/22-passive-aggressive/tf-23-monadic.py
index 8fd1bc4..01d4127 100644
--- a/22-passive-aggressive/tf-23-monadic.py
+++ b/22-passive-aggressive/tf-23-monadic.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-from __future__ import print_function
 import sys, re, operator, string
 
 #
@@ -68,7 +67,7 @@ def sort(word_freqs):
     assert(type(word_freqs) is dict), "I need a dictionary! I quit!"
     assert(word_freqs != {}), "I need a non-empty dictionary! I quit!"
 
-    return sorted(word_freqs.iteritems(), key=operator.itemgetter(1), reverse=True)
+    return sorted(word_freqs.items(), key=operator.itemgetter(1), reverse=True)
 
 def top25_freqs(word_freqs):
     assert(type(word_freqs) is list), "I need a list! I quit!"
diff --git a/23-declared-intentions/tf-23.py b/23-declared-intentions/tf-23.py
index 1b703d1..347776d 100644
--- a/23-declared-intentions/tf-23.py
+++ b/23-declared-intentions/tf-23.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-from __future__ import print_function
 import sys, re, operator, string, inspect
 
 #
@@ -42,7 +41,7 @@ def frequencies(word_list):
 
 @AcceptTypes(dict)
 def sort(word_freq):
-    return sorted(word_freq.iteritems(), key=operator.itemgetter(1), reverse=True)
+    return sorted(word_freq.items(), key=operator.itemgetter(1), reverse=True)
 
 word_freqs = sort(frequencies(extract_words(sys.argv[1])))
 for (w, c) in word_freqs[0:25]:
diff --git a/24-quarantine/tf-24.py b/24-quarantine/tf-24.py
index 3a69824..bae6c50 100644
--- a/24-quarantine/tf-24.py
+++ b/24-quarantine/tf-24.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-from __future__ import print_function
 import sys, re, operator, string
 
 #
@@ -58,7 +57,7 @@ def frequencies(word_list):
     return word_freqs
 
 def sort(word_freq):
-    return sorted(word_freq.iteritems(), key=operator.itemgetter(1), reverse=True)
+    return sorted(word_freq.items(), key=operator.itemgetter(1), reverse=True)
 
 def top25_freqs(word_freqs):
     top25 = ""
diff --git a/25-persistent-tables/tf-25.py b/25-persistent-tables/tf-25.py
index 67dd107..8ed7224 100755
--- a/25-persistent-tables/tf-25.py
+++ b/25-persistent-tables/tf-25.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-from __future__ import print_function
 import sys, re, string, sqlite3, os.path
 
 #
diff --git a/26-spreadsheet/tf-26.py b/26-spreadsheet/tf-26.py
index b07656c..5f4ebe2 100755
--- a/26-spreadsheet/tf-26.py
+++ b/26-spreadsheet/tf-26.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-from __future__ import print_function
 import sys, re, itertools, operator
 
 #
@@ -9,18 +8,18 @@ import sys, re, itertools, operator
 all_words = [(), None]
 stop_words = [(), None]
 non_stop_words = [(), lambda : \
-                          map(lambda w : \
+                          list(map(lambda w : \
                             w if w not in stop_words[0] else '',\
-                              all_words[0])]
+                              all_words[0]))]
 unique_words = [(),lambda : 
                     set([w for w in non_stop_words[0] if w!=''])]
 counts = [(), lambda : 
-                map(lambda w, word_list : word_list.count(w), \
+                list(map(lambda w, word_list : word_list.count(w), \
                     unique_words[0], \
                     itertools.repeat(non_stop_words[0], \
-                                   len(unique_words[0])))]
+                                   len(unique_words[0]))))]
 sorted_data = [(), lambda : sorted(zip(list(unique_words[0]), \
-                                       counts[0]), \
+                                       list(counts[0])), \
                                    key=operator.itemgetter(1), 
                                    reverse=True)]
 
@@ -39,7 +38,6 @@ def update():
         if c[1] != None:
             c[0] = c[1]() 
 
-
 # Load the fixed data into the first 2 columns
 all_words[0] = re.findall('[a-z]{2,}', open(sys.argv[1]).read().lower())
 stop_words[0] = set(open('../stop_words.txt').read().split(','))
diff --git a/27-lazy-rivers/tf-27.py b/27-lazy-rivers/tf-27.py
index b1cdbb7..fe0e675 100755
--- a/27-lazy-rivers/tf-27.py
+++ b/27-lazy-rivers/tf-27.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-from __future__ import print_function
 import sys, operator, string
 
 def characters(filename):
@@ -36,9 +35,9 @@ def count_and_sort(filename):
     for w in non_stop_words(filename):
         freqs[w] = 1 if w not in freqs else freqs[w]+1
         if i % 5000 == 0:
-            yield sorted(freqs.iteritems(), key=operator.itemgetter(1), reverse=True)
+            yield sorted(freqs.items(), key=operator.itemgetter(1), reverse=True)
         i = i+1
-    yield sorted(freqs.iteritems(), key=operator.itemgetter(1), reverse=True)
+    yield sorted(freqs.items(), key=operator.itemgetter(1), reverse=True)
 #
 # The main function
 #
diff --git a/28-actors/tf-28.py b/28-actors/tf-28.py
index 57ec146..34df07a 100755
--- a/28-actors/tf-28.py
+++ b/28-actors/tf-28.py
@@ -1,9 +1,7 @@
 #!/usr/bin/env python
-
-from __future__ import print_function
 import sys, re, operator, string
 from threading import Thread
-from Queue import Queue
+from queue import Queue
 
 class ActiveWFObject(Thread):
     def __init__(self):
@@ -95,7 +93,7 @@ class WordFrequencyManager(ActiveWFObject):
 
     def _top25(self, message):
         recipient = message[0]
-        freqs_sorted = sorted(self._word_freqs.iteritems(), key=operator.itemgetter(1), reverse=True)
+        freqs_sorted = sorted(self._word_freqs.items(), key=operator.itemgetter(1), reverse=True)
         send(recipient, ['top25', freqs_sorted])
 
 class WordFrequencyController(ActiveWFObject):
diff --git a/29-dataspaces/tf-29.py b/29-dataspaces/tf-29.py
index 76afb9e..81d2fbb 100755
--- a/29-dataspaces/tf-29.py
+++ b/29-dataspaces/tf-29.py
@@ -1,10 +1,9 @@
 #!/usr/bin/env python
-from __future__ import print_function
-import re, sys, operator, Queue, threading
+import re, sys, operator, queue, threading
 
 # Two data spaces
-word_space = Queue.Queue()
-freq_space = Queue.Queue()
+word_space = queue.Queue()
+freq_space = queue.Queue()
 
 stopwords = set(open('../stop_words.txt').read().split(','))
 
@@ -15,7 +14,7 @@ def process_words():
     while True:
         try:
             word = word_space.get(timeout=1)
-        except Queue.Empty:
+        except queue.Empty:
             break
         if not word in stopwords:
             if word in word_freqs:
@@ -42,12 +41,12 @@ for i in range(5):
 word_freqs = {}
 while not freq_space.empty():
     freqs = freq_space.get()
-    for (k, v) in freqs.iteritems():
+    for (k, v) in freqs.items():
         if k in word_freqs:
             count = sum(item[k] for item in [freqs, word_freqs])
         else:
             count = freqs[k]
         word_freqs[k] = count
         
-for (w, c) in sorted(word_freqs.iteritems(), key=operator.itemgetter(1), reverse=True)[:25]:
+for (w, c) in sorted(word_freqs.items(), key=operator.itemgetter(1), reverse=True)[:25]:
     print(w, '-', c)
diff --git a/30-map-reduce/tf-30.py b/30-map-reduce/tf-30.py
index ce2db3b..cd7b866 100755
--- a/30-map-reduce/tf-30.py
+++ b/30-map-reduce/tf-30.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-from __future__ import print_function
 import sys, re, operator, string
 from functools import reduce
 
@@ -51,12 +50,13 @@ def count_words(pairs_list_1, pairs_list_2):
     and returns a list of pairs [(w1, frequency), ...],
     where frequency is the sum of all the reported occurrences
     """
-    mapping = dict((k, v) for k, v in pairs_list_1)
-    for p in pairs_list_2:
-        if p[0] in mapping:
-            mapping[p[0]] += p[1]
-        else:
-            mapping[p[0]] = 1
+    mapping = {}
+    for pl in [pairs_list_1, pairs_list_2]:
+        for p in pl:
+            if p[0] in mapping:
+                mapping[p[0]] += p[1]
+            else:
+                mapping[p[0]] = p[1]
     return mapping.items()
 
 #
@@ -74,7 +74,6 @@ def sort(word_freq):
 # The main function
 #
 splits = map(split_words, partition(read_file(sys.argv[1]), 200))
-splits.insert(0, []) # Normalize input to reduce
 word_freqs = sort(reduce(count_words, splits))
 
 for (w, c) in word_freqs[0:25]:
diff --git a/31-double-map-reduce/tf-31.py b/31-double-map-reduce/tf-31.py
index 997c05f..33620d4 100755
--- a/31-double-map-reduce/tf-31.py
+++ b/31-double-map-reduce/tf-31.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-from __future__ import print_function
 import sys, re, operator, string
 from functools import reduce
 
diff --git a/32-trinity/tf-32-active.py b/32-trinity/tf-32-active.py
index 4b14575..78141e8 100755
--- a/32-trinity/tf-32-active.py
+++ b/32-trinity/tf-32-active.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-from __future__ import print_function
 import sys, operator, string, os, threading, re
 from util import getch, cls, get_input
 from time import sleep
@@ -15,7 +14,7 @@ class FreqObserver(threading.Thread):
         self.daemon,self._end = True, False
         # freqs is the part of the model to be observed
         self._freqs = freqs
-        self._freqs_0 = sorted(self._freqs.iteritems(), key=operator.itemgetter(1), reverse=True)[:25]
+        self._freqs_0 = sorted(self._freqs.items(), key=operator.itemgetter(1), reverse=True)[:25]
         self.start()
 
     def run(self):
@@ -29,7 +28,7 @@ class FreqObserver(threading.Thread):
 
     def _update_view(self):
         lock.acquire()
-        freqs_1 = sorted(self._freqs.iteritems(), key=operator.itemgetter(1), reverse=True)[:25]
+        freqs_1 = sorted(self._freqs.items(), key=operator.itemgetter(1), reverse=True)[:25]
         lock.release()
         if (freqs_1 != self._freqs_0):
             self._update_display(freqs_1)
diff --git a/32-trinity/tf-32-reactive.py b/32-trinity/tf-32-reactive.py
index 65c9399..02c3de1 100644
--- a/32-trinity/tf-32-reactive.py
+++ b/32-trinity/tf-32-reactive.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-from __future__ import print_function
 import sys, re, operator, collections
 
 class WordFrequenciesModel:
@@ -29,7 +28,7 @@ class WordFrequenciesView:
         model.register(self)
 
     def render(self):
-        sorted_freqs = sorted(self._model.freqs.iteritems(), key=operator.itemgetter(1), reverse=True)
+        sorted_freqs = sorted(self._model.freqs.items(), key=operator.itemgetter(1), reverse=True)
         for (w, c) in sorted_freqs[:25]:
             print(w, '-', c)
 
diff --git a/32-trinity/tf-32.py b/32-trinity/tf-32.py
index fee95d6..3044e13 100755
--- a/32-trinity/tf-32.py
+++ b/32-trinity/tf-32.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-from __future__ import print_function
 import sys, re, operator, collections
 
 class WordFrequenciesModel:
@@ -23,7 +22,7 @@ class WordFrequenciesView:
         self._model = model
 
     def render(self):
-        sorted_freqs = sorted(self._model.freqs.iteritems(), key=operator.itemgetter(1), reverse=True)
+        sorted_freqs = sorted(self._model.freqs.items(), key=operator.itemgetter(1), reverse=True)
         for (w, c) in sorted_freqs[0:25]:
             print(w, '-', c)
 
diff --git a/33-restful/tf-33.py b/33-restful/tf-33.py
index 483e9a8..c83ac47 100755
--- a/33-restful/tf-33.py
+++ b/33-restful/tf-33.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-from __future__ import print_function
 import re, string, sys
 
 with open("../stop_words.txt") as f:
@@ -32,9 +31,8 @@ def upload_post_handler(args):
         with open(filename) as f:
             for w in [x.lower() for x in re.split("[^a-zA-Z]+", f.read()) if len(x) > 0 and x.lower() not in stops]:
                 word_freqs[w] = word_freqs.get(w, 0) + 1
-        word_freqsl = word_freqs.items()
-        word_freqsl.sort(key=lambda x: x[1], reverse=True)
-        data[filename] = word_freqsl
+        word_freqsl = list(word_freqs.items())
+        data[filename] = sorted(word_freqsl, key=lambda x: x[1], reverse=True)
 
     if args == None:
         return error_state()
@@ -42,6 +40,7 @@ def upload_post_handler(args):
     try:
         create_data(filename)
     except:
+        print("Unexpected error: %s" % sys.exc_info()[0])
         return error_state()
     return word_get_handler([filename, 0])
 
diff --git a/34-the-c-flow/tf-34.py b/34-the-c-flow/tf-34.py
index 2f76dd2..b64dd6f 100755
--- a/34-the-c-flow/tf-34.py
+++ b/34-the-c-flow/tf-34.py
@@ -1,6 +1,4 @@
 #!/usr/bin/env python
-
-from __future__ import print_function
 import sys, re, operator, string, inspect
 
 # Reusing the defensive style program to illustrate this
@@ -63,7 +61,7 @@ def sort(word_freq):
     sorted by frequency 
     """
     if type(word_freq) is dict and word_freq != {}:
-        return sorted(word_freq.iteritems(), key=operator.itemgetter(1), reverse=True)
+        return sorted(word_freq.items(), key=operator.itemgetter(1), reverse=True)
     else:
         return []
 
diff --git a/README.md b/README.md
index 6d53b9f..183a554 100644
--- a/README.md
+++ b/README.md
@@ -9,6 +9,9 @@ with the following command line:
 python tf-NN.py ../pride-and-prejudice.txt
 ```
 
+NOTE: the code in the master branch is written for Python 3. If you are looking
+for a version for Python 2.7, check out the 2.7 branch or the v1.0 release.
+
 Explanations and historical context for all these styles can be found in the
 companion book [Exercises in Programming Style](http://www.amazon.com/Exercises-Programming-Style-Cristina-Videira/dp/1482227371/).