'Iterate over the nodes. Use the expression \'for n in G\'.
Returns
niter : iterator
An iterator over all nodes in the graph.
Examples
>>> G = nx.path_graph(4)  # or DiGraph, MultiGraph, MultiDiGraph, etc
>>> [n for n in G]
[0, 1, 2, 3]'

def __iter__(self):

    return iter(self._node)
