'Creates a Graph instance from the filename.'

@staticmethod
def create_graph(filename):

    fh = open(filename, mode='rb')
    nodes = struct.unpack('<H', fh.read(2))[0]
    graph = nx.Graph()
    for from_node in range(nodes):
        edges = struct.unpack('<H', fh.read(2))[0]
        for edge in range(edges):
            to_node = struct.unpack('<H', fh.read(2))[0]
            graph.add_edge(from_node, to_node)
    fh.close()
    return graph
