code: def create_channel(cls, address="spanner.googleapis.com:443", credentials=None):
          
          grpc_gcp_config = grpc_gcp.api_config_from_text_pb(
              pkg_resources.resource_string(__name__, _SPANNER_GRPC_CONFIG)
          )
          options = [(grpc_gcp.API_CONFIG_CHANNEL_ARG, grpc_gcp_config)]
          return google.api_core.grpc_helpers.create_channel(
              address, credentials=credentials, scopes=cls._OAUTH_SCOPES
          )
docs: Create and return a gRPC channel object.
  
          Args:
              address (str): The host for the channel to use.
              credentials (~.Credentials): The
                  authorization credentials to attach to requests. These
                  credentials identify this application to the service. If
                  none are specified, the client will attempt to ascertain
                  the credentials from the environment.
  
          Returns:
              grpc.Channel: A gRPC channel object.