Error executing create_output_from_dir.py

Executing with no parameters like this;
> python create_output_from_dir.py

causes a TypeError to be thrown

Traceback (most recent call last):
  File "create_output_from_dir.py", line 24, in <module>
    receive_sensitivity = (0 - (receive_sensitivity))
TypeError: unsupported operand type(s) for -: 'int' and 'str'