Is a button depressed?
        True if a button is pressed, false otherwise.

def query_state(self, StateType):
        """
        Is a button depressed?
        True if a button is pressed, false otherwise.
        """
        if StateType == M_LEFT:
            # Checking left mouse button
            return self.left_pressed
        elif StateType == M_MIDDLE:
            # Checking middle mouse button
            return self.middle_pressed
        elif StateType == M_RIGHT:
            # Checking right mouse button
            return self.right_pressed