How to run a subprocess with Python, wait for it to exit and get the full stdout as a string?

Question

So I noticed subprocess.call while it waits for the command to finish before proceeding with the python script, I have no way of getting the stdout, except with

Answer 1

With Python 3.8 this workes for me. For instance to execute a python script within the venv:

    import subprocess
    import sys
    res = subprocess.run([
              sys.executable,            # venv3.8/bin/python
              'main.py', '--help',], 
            stdout=PIPE, 
            text=True)
    print(res.stdout)