I never used it, but I presume you start it with some program that ends with ".py" If yes, then if you open that file with some text editor, the first line points it to python..
So replace that path with whatever "which python" returns, e.g. #!/usr/bin/python or #!/bin/python
Wow that's progress! Now it errors saying cant open 'python3' The original line was wrong and I changed it but it looked like this #!/usr/bin/env python3. The which cmd says its