Cannot run custom written script

[Parsia Hedayat]

I've been following the tutorial on the VMTK website to write custom PypeS scripts and I'm encountering an issue. 

#! /vmtk/bin/python3.6

import sys

from vmtk import pypes

from vmtk import vmtkscripts

customScript = 'customScript'

class customScript(pypes.pypeScript):

   

   def __init__(self):

       pypes.pypeScript.__init__(self)

    def Execute(self):

       pass

   

if __name__=='__main__':

    main = pypes.pypeMain()

   main.Arguments = sys.argv

   main.Execute()

Above is the code I have written, saved in a file named customScript.py. I'm running macOS High Sierra 10.13.6. After changing the permissions of the file and attempting to run it using ./customScript.py, it tells me that there is "No module named 'vmtk.customScript'". I'm not necessarily sure what the issue is. The place I thought an issue might be occurring is where I defined the interpreter; however, when I attempt to leave the interpreter as shown in the example, I get a "Bad interpreter" error. Any ideas?