def on_key_release(self, button: int, modifiers: int):
    'Called when the user releases a key.'
    if (button in self.left):
        self.left_pressed = False
    elif (button in self.right):
        self.right_pressed = False
Called when the user releases a key.
def on_key_release(self, button: int, modifiers: int):
    
    if (button in self.left):
        self.left_pressed = False
    elif (button in self.right):
        self.right_pressed = False