When I import a Module it wont run

[PyNovice]

I posted previously without reading your reply.
This is what Ive now done

import os
import globalVariables as gv

def listCWD():
    """ This section lists everything in the current working directory

    the if condition means that the code beneath it will only run if this file(__name__) is the Main Module(__main__)
    e.g it will not run if this module has been imported into another module. """
   

    try:
      gv.directoryList = os.listdir(gv.directoryIn)
      print('directoryList =\n',gv.directoryList)

    except FileNotFoundError:
      print('FileNotFoundError:\na List for the Directory gv.directoryIn cannnot be created\nbecause the Global Variable gv.directoryIn is an empty string.\n'
                      'To correct this either:\na)run the returnCWD function in this Module to assign a directory to gv.directoryIn or\nb)open the globalVariables.py file and setgv.directoryIn to = None')

    except TypeError:
      print('TypeError:\na List for the Directory gv.directoryIn cannnot be created\nbecause the Global Variable gv.directoryIn has been assigned to equal either:\n'
                     'a)List\nb)Set\nc)Tuple\n'
                     'To correct this either:\na)run the returnCWD function in this M odule to assign a directory to gv.directoryIn or\nb)open the globalVariables.py file and setgv.directoryIn to = None')

    except NameError:
      print('NameError:\nbecause of the Syntax Error on import a NameError now occurs in the functions code\n'
               'To correct the SyntaxError above open the globalVariables.py file and do either of the solutions below\n'
               'a)make directoryIn = an empty string\nb)make directoryIn = None')

listCWD()

if __name__ == '__main__':
    listCWD()

However after running the returnFileList Module I now get the following result which is including the FileNotFoundError that would otherwise be found if the listCwd.py Module was run on its own. I hope ive expalined that correctly.

Python 3.7.4 (tags/v3.7.4:e09359112e, Jul  8 2019, 19:29:22) [MSC v.1916 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license()" for more information.
>>> 
 RESTART: G:\2 Employment and Education\2 Education\2 Projects(All)\6 My Python Projects\MyPyProject\FileManagerProgram\1 Successfuly Tested\3 Working on - need to steeamline(22 09 19 9pm)\For Qs on Python Forum\returnFileList.py 
The os module has been imported
The globalVariables module has been imported
The returnCWD module has been imported
FileNotFoundError:
a List for the Directory gv.directoryIn cannnot be created
because the Global Variable gv.directoryIn is an empty string.
To correct this either:
a)run the returnCWD function in this Module to assign a directory to gv.directoryIn or
b)open the globalVariables.py file and setgv.directoryIn to = None
The listCWD module has been imported

The Current Working Directory is
 G:\2 Employment and Education\2 Education\2 Projects(All)\6 My Python Projects\MyPyProject\FileManagerProgram\1 Successfuly Tested\3 Working on - need to steeamline(22 09 19 9pm)\For Qs on Python Forum

returnCWD ran corrrectly

directoryList =
 ['globalVariables.py', 'listCWD.py', 'returnCWD.py', 'returnFileList.py', '__pycache__']
listCWD ran corrrectly