def METHOD_NAME(self):
    # First create a flat list of all elements, including elements that are
    # part of a group. Then we show them, clearing the display on the first,
    # and updating the display on the last.
    t0 = self.experiment.clock.time()
    elements = [e for g in self._elements.values() if g.visible for e in g]
    self._background.present(clear=True, update=not elements)
    while elements:
        e = elements.pop(0)
        e.METHOD_NAME(clear=False, update=not elements)
    t1 = self.experiment.clock.time()
    if t1 - t0 > self.MAX_SHOW_DT:
        oslogger.warning('Canvas.show() took {0} ms'.format(t1 - t0))
    return t1