docs: def client(host='localhost', port=2379,
             ca_cert=None, cert_key=None, cert_cert=None,
             timeout=None, protocol="http"):
      """Return an instance of an Etcd3Client."""
      return Etcd3Client(host=host,
                         port=port,
                         ca_cert=ca_cert,
                         cert_key=cert_key,
                         cert_cert=cert_cert,
                         timeout=timeout,
                         protocol=protocol)