Here is how you can print the full path to the Python interpreter.

#!/usr/bin/python3
import sys
print(f"Python interpreter = {sys.executable}")

Which should print something like this.

Python interpreter = /usr/bin/python

Or like this.

Python interpreter = /usr/bin/python3

Take for example this Python script which uses subprocess.

import sys
import subprocess
command = sys.executable+" --version"
stdout, stderr = subprocess.Popen(command, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE).communicate()
stdout = stdout.decode('utf-8').strip()
stderr = stderr.decode('utf-8').strip()
if stdout:
  print(command +" = " +stdout)
if stderr:
  print(command +" = " +stderr)

Running this script should return something like this.

~]$ python testing.py 
/usr/bin/python --version = Python 2.7.5

~]$ python3 testing.py 
/usr/bin/python3 --version = Python 3.6.8

~]$ /usr/local/bin/python3.12.0/bin/python3.12 testing.py 
/usr/local/bin/python3.12.0/bin/python3.12 --version = Python 3.12.0