node_equal

        High-level api: Evaluate whether two nodes are equal.

        Parameters
        ----------

        node1 : `Element`
            A node in a model tree.

        node2 : `Element`
            A node in another model tree.

        Returns
        -------

        bool
            True if node1 and node2 are equal.

def node_equal(node1, node2):
        '''node_equal

        High-level api: Evaluate whether two nodes are equal.

        Parameters
        ----------

        node1 : `Element`
            A node in a model tree.

        node2 : `Element`
            A node in another model tree.

        Returns
        -------

        bool
            True if node1 and node2 are equal.
        '''

        if ModelDiff.node_less(node1, node2) and \
           ModelDiff.node_less(node2, node1):
            return True
        else:
            return False