python returns error when using bbox with pyscreenshot

my code

im = pyscreenshot.grab(bbox=(on_click.px, on_click.py, on_click.rx, on_click.ry))
im.save('img.png')

returned error:

Traceback (most recent call last):
  File "c:\Users\cww\Downloads\Typeracer Bot\typeracerbot.py", line 21, in <module>
    im = pyscreenshot.grab(bbox=(on_click.px, on_click.py, on_click.rx, on_click.ry))
  File "C:\Users\cww\AppData\Local\Programs\Python\Python310\lib\site-packages\pyscreenshot\__init__.py", line 27, in grab
    raise ValueError("bbox x2<=x1")
ValueError: bbox x2<=x1

im trying to save an image of the whole screen with a click of the mouse and then print that text where i put the mouse (the img printed gets saved in the folder)