@classmethod
def to_yaml(cls, representer, node):
    """Create a YAML representation of a DAGReference, carrying only the
        _data attribute over...
        
        As YAML expects scalar data to be str-like, a type cast is done. The
        subclasses that rely on certain argument types should take care that
        they can parse arguments that are str-like.
        """
    return representer.represent_scalar(cls.yaml_tag, str(node._data))
