def __iter__(self):
        '''an iterator over MultiNodes
        '''
        def traverse(current, nodes=[]):

            # Case 1: We are at the root (and have list)
            if isinstance(current.children, list):
                children = current.children
            else:
                children = []
                for tag in current.children:
                    children += current.children[tag]

            nodes = nodes + children

            # Traverse remainder of children
            for child in children:
                traverse(child, nodes)

            for node in nodes:
                yield node

        # Call function recursively
        nodes = []
        for node in traverse(self.root, nodes):
            yield node