diff --git a/20-defensive/tf-20.py b/20-defensive/tf-20.py old mode 100644 new mode 100755 diff --git a/21-tantrum/tf-21.py b/21-tantrum/tf-21.py old mode 100644 new mode 100755 diff --git a/34-the-c-flow/tf-34.py b/34-the-c-flow/tf-34.py old mode 100644 new mode 100755