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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 modify(self, sp=None, ip_port=None, ip_address=None, netmask=None, v6_prefix_length=None, gateway=None, vlan_id=None):
 """ Modifies a replication interface. :param sp: same as the one in `create` method. :param ip_port: same as the one in `create` method. :param ip_address: same as the one in `create` method. :param netmask: same as the one in `create` method. :param v6_prefix_length: same as the one in `create` method. :param gateway: same as the one in `create` method. :param vlan_id: same as the one in `create` method. """

        req_body = self._cli.make_body(sp=sp, ipPort=ip_port,
                                       ipAddress=ip_address, netmask=netmask,
                                       v6PrefixLength=v6_prefix_length,
                                       gateway=gateway, vlanId=vlan_id)

        resp = self.action('modify', **req_body)
        resp.raise_if_err()
        return resp