def METHOD_NAME(self):
    ns_map: Dict = {}
    self.assertEqual("ns0", load_prefix("a", ns_map))
    self.assertEqual("ns0", load_prefix("a", ns_map))
    self.assertEqual("ns0", load_prefix("a", ns_map))
    self.assertEqual("xs", load_prefix(Namespace.XS.uri, ns_map))
    self.assertEqual("soapenv", load_prefix(Namespace.SOAP_ENV.uri, ns_map))
    expected = {
        "ns0": "a",
        "soapenv": "http://schemas.xmlsoap.org/soap/envelope/",
        "xs": "http://www.w3.org/2001/XMLSchema",
    }
    self.assertEqual(expected, ns_map)