Parses a History Node object from either a dict or a tuple.

        Args:
            h_node: A dict with name/url/description fields or a 3-element
                tuple.

        Returns:
            History node.

def parse_history_node(h_node):
        """
        Parses a History Node object from either a dict or a tuple.

        Args:
            h_node: A dict with name/url/description fields or a 3-element
                tuple.

        Returns:
            History node.
        """
        if isinstance(h_node, dict):
            return HistoryNode.from_dict(h_node)

        else:
            if len(h_node) != 3:
                raise ValueError("Invalid History node, "
                                 "should be dict or (name, version, "
                                 "description) tuple: {}".format(h_node))
            return HistoryNode(h_node[0], h_node[1], h_node[2])