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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_connection(self, from_obj, to_obj):
 """ Returns a ``Connection`` instance for the given objects or ``None`` if there's no connection. """

        self._validate_ctypes(from_obj, to_obj)
        try:
            return self.connections.get(from_pk=from_obj.pk, to_pk=to_obj.pk)
        except Connection.DoesNotExist:
            return None