We run both Python 2.x and Python 3.x on our servers.
The path to the default Python 2.x interpreter is:
/usr/bin/python
If you want to use Python 3.x, the path to the interpreter is:
/usr/bin/python3
Your Python 2.x scripts need to begin with this line:
#!/usr/bin/python
The Python 3.x scripts should start with:
#!/usr/bin/python3