def METHOD_NAME(self, event):
    """The ViewBox mouse event handler
    Parameters
    ----------
    event : instance of Event
        The mouse event.
    """
    # When the attached ViewBox reseives a mouse event, it is sent to the
    # camera here.
    self.mouse_pos = event.pos[:2]
    if event.type == 'mouse_wheel':
        # wheel rolled; adjust the magnification factor and hide the 
        # event from the superclass
        m = self.mag_target 
        m *= 1.2 ** event.delta[1]
        m = m if m > 1 else 1
        self.mag_target = m
    else:
        # send everything _except_ wheel events to the superclass
        super(MagnifyCamera, self).METHOD_NAME(event)
    # start the timer to smoothly modify the transform properties. 
    if not self.timer.running:
        self.timer.start()
    self._update_transform()