diff --git a/21-constructivist/tf-21.py b/21-constructivist/tf-21.py
index 56ab7e6..9403037 100755
--- a/21-constructivist/tf-21.py
+++ b/21-constructivist/tf-21.py
@@ -1,16 +1,10 @@
 #!/usr/bin/env python
-
 import sys, re, operator, string, inspect
 
 #
 # The functions
 #
 def extract_words(path_to_file):
-    """
-    Takes a path to a file and returns the non-stop
-    words, after properly removing nonalphanumeric chars
-    and normalizing for lower case
-    """
     if type(path_to_file) is not str or not path_to_file:
         return []
 
@@ -23,6 +17,11 @@ def extract_words(path_to_file):
     
     pattern = re.compile('[\W_]+')
     word_list = pattern.sub(' ', str_data).lower().split()
+    return word_list
+
+def remove_stop_words(word_list):
+    if type(word_list) is not list:
+        return [] 
 
     try:
         with open('../stop_words.txt') as f:
@@ -35,10 +34,6 @@ def extract_words(path_to_file):
     return [w for w in word_list if not w in stop_words]
 
 def frequencies(word_list):
-    """
-    Takes a list of words and returns a dictionary associating
-    words with frequencies of occurrence
-    """
     if type(word_list) is not list or word_list == []:
         return {}
 
@@ -51,11 +46,6 @@ def frequencies(word_list):
     return word_freqs
 
 def sort(word_freq):
-    """
-    Takes a dictionary of words and their frequencies
-    and returns a list of pairs where the entries are
-    sorted by frequency 
-    """
     if type(word_freq) is not dict or word_freq == {}:
         return []
 
@@ -65,7 +55,7 @@ def sort(word_freq):
 # The main function
 #
 filename = sys.argv[1] if len(sys.argv) > 1 else "../input.txt"
-word_freqs = sort(frequencies(extract_words(filename)))
+word_freqs = sort(frequencies(remove_stop_words(extract_words(filename))))
 
 for tf in word_freqs[0:25]:
     print tf[0], ' - ', tf[1]