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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 _parse_phone_and_hash(self, phone, phone_hash):
 """ Helper method to both parse and validate phone and its hash. """

        phone = utils.parse_phone(phone) or self._phone
        if not phone:
            raise ValueError(
                'Please make sure to call send_code_request first.'
            )

        phone_hash = phone_hash or self._phone_code_hash.get(phone, None)
        if not phone_hash:
            raise ValueError('You also need to provide a phone_code_hash.')

        return phone, phone_hash