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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_children(self):
 """Return all the children of this object."""

        if hasattr(self, '_cached_children'):
            children = self._toplevel().objects.filter(
                pk__in=[n.pk for n in self._cached_children]
            )
            children._result_cache = self._cached_children
            return children
        else:
            return self.get_descendants(include_self=False, depth=1)