'Return an iterator over the incoming edges.
in_edges(self, nbunch=None, data=False, default=None):
Parameters
nbunch : iterable container, optional (default= all nodes)
A container of nodes.  The container will be iterated
through once.
data : string or bool, optional (default=False)
The edge attribute returned in 3-tuple (u, v, ddict[data]).
If True, return edge attribute dict in 3-tuple (u, v, ddict).
If False, return 2-tuple (u, v).
default : value, optional (default=None)
Value used for edges that dont have the requested attribute.
Only relevant if data is not True or False.
Returns
in_edge : iterator
An iterator over (u, v) or (u, v, d) tuples of incoming edges.
See Also
edges : return an iterator over edges'

@property
def in_edges(self):

    self.__dict__['in_edges'] = in_edges = InEdgeView(self)
    return in_edges
