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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_catalog(self):
 """ Get an obspy catalog object from the party. :returns: :class:`obspy.core.event.Catalog` .. rubric:: Example 4 """

        catalog = Catalog()
        for fam in self.families:
            if len(fam.catalog) != 0:
                catalog.events.extend(fam.catalog.events)
        return catalog