code: def client(host='localhost', port=2379,
             ca_cert=None, cert_key=None, cert_cert=None, timeout=None,
             user=None, password=None, grpc_options=None):
      
      return Etcd3Client(host=host,
                         port=port,
                         ca_cert=ca_cert,
                         cert_key=cert_key,
                         cert_cert=cert_cert,
                         timeout=timeout,
                         user=user,
                         password=password,
                         grpc_options=grpc_options)
docs: Return an instance of an Etcd3Client.