'Return an iterator for (node, in-degree) or in-degree for single node.
in_degree(self, nbunch=None, weight=None)
The node in-degree is the number of edges pointing in to the node.
This function returns the in-degree for a single node or an iterator
for a bunch of nodes or if nothing is passed as argument.
Parameters
nbunch : iterable container, optional (default=all nodes)
A container of nodes.  The container will be iterated
through once.
weight : string or None, optional (default=None)
The edge attribute that holds the numerical value used
as a weight.  If None, then each edge has weight 1.
The degree is the sum of the edge weights adjacent to the node.
Returns
If a single node is requested
deg : int
In-degree of the node
OR if multiple nodes are requested
nd_iter : iterator
The iterator returns two-tuples of (node, in-degree).
See Also
degree, out_degree
Examples
>>> G = nx.DiGraph()
>>> nx.add_path(G, [0, 1, 2, 3])
>>> G.in_degree(0) # node 0 with degree 0
0
>>> list(G.in_degree([0, 1]))
[(0, 0), (1, 1)]'

@property
def in_degree(self):

    self.__dict__['in_degree'] = in_degree = InDegreeView(self)
    return in_degree
