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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 describe(self, req=None, resp=None, **kwargs):
 """Extend default endpoint description with serializer description."""

        return super().describe(
            req, resp,
            type='list',
            fields=self.serializer.describe() if self.serializer else None,
            **kwargs
        )