"UnboundLocalError: local variable 'status' referenced before assignment" and "status_1" is not accessed by Pylance

Question

This script should tell me if another python file is running or not running and prints file on/file off every time the file stops/starts running:

import psutil
import os
status = True
status_1 = True
while True:
    def is_running(script):
        for q in psutil.process_iter():
            if q.name().startswith('python'):
                if len(q.cmdline())>1 and script in q.cmdline()[1] and q.pid !=os.getpid():
                    if status:
                        status_1 = True #"status_1" is not accessed by Pylance
                        status = False
                        print('file on')
    if not is_running("test.py"):
        if status_1:
            status = True
            status_1 = False
            print('file off')

The error:

Traceback (most recent call last):
  File "c:\Users\Win10\file.py", line 27, in <module>
    if not is_running("test.py"):
  File "c:\Users\Win10\file.py", line 23, in is_running
    if status:
UnboundLocalError: local variable 'status' referenced before assignment

I am using vs code by the way.

Answer 1

The line status = False is a global variable assignment in a function, and therefore there must be a global declaration at the start of the function: global status .

    def is_running(script):
        global status
        for q in psutil.process_iter():
            if q.name().startswith('python'):
                if len(q.cmdline())>1 and script in q.cmdline()[1] and q.pid !=os.getpid():
                    if status:
                        status_1 = True #"status_1" is not accessed by Pylance
                        status = False
                        print('file on')