pygame mouse_pos is always the bottom right code example

Example: pygame get mouse position

x,y = pygame.mouse.get_pos()
#get the mouse cursor position
#get_pos() -> (x, y)
#Returns the X and Y position of the mouse cursor.
#The position is relative to the top-left corner of the display.
#The cursor position can be located outside of the display window,
#but is always constrained to the screen.