def METHOD_NAME(self, context):
    """Return the handle associated with the gRPC call.
    Args:
        context (object): Context of the request.
    Returns:
        str: The model handle.
    """
    metadata = context.invocation_metadata()
    metadata_dict = {}
    for key, value in metadata:
        metadata_dict[key] = value
    return metadata_dict[self.HANDLE_KEY]