'Initialize DiGraphMatcher.
G1 and G2 should be nx.Graph or nx.MultiGraph instances.
Examples
To create a GraphMatcher which checks for syntactic feasibility:
>>> from networkx.algorithms import isomorphism
>>> G1 = nx.DiGraph(nx.path_graph(4, create_using=nx.DiGraph()))
>>> G2 = nx.DiGraph(nx.path_graph(4, create_using=nx.DiGraph()))
>>> DiGM = isomorphism.DiGraphMatcher(G1,G2)'

def __init__(self, G1, G2):

    super(DiGraphMatcher, self).__init__(G1, G2)
