<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def bbox(self):
 """ Bounding box of the live shape. :return: :py:class:`~psd_tools.psd.descriptor.Descriptor` """

        bbox = self._data.get(b'keyOriginShapeBBox')
        if bbox:
            return (
                bbox.get(b'Left').value,
                bbox.get(b'Top ').value,
                bbox.get(b'Rght').value,
                bbox.get(b'Btom').value,
            )
        return (0, 0, 0, 0)