def METHOD_NAME(self, *largs):
    sample = self._camerasink.emit('pull-sample')
    if sample is None:
        return False
    self._sample = sample
    if self._texturesize is None:
        # try to get the camera image size
        for pad in self._decodebin.srcpads:
            s = pad.get_current_caps().get_structure(0)
            self._texturesize = (
                s.get_value('width'),
                s.get_value('height'))
            Clock.schedule_once(self._update)
            return False
    Clock.schedule_once(self._update)
    return False