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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 process_m2m_through_save(self, obj, created=False, **kwargs):
 """Process M2M post save for custom through model."""

        # We are only interested in signals that establish relations.
        if not created:
            return

        self._process_m2m_through(obj, 'post_add')