def __iadd__(self, node):
        "Add node to graph with no edges"
        node = self.pack_source(node)
        if self.d not in node:
            self.d[node] = {} # INITIALIZE TOPLEVEL DICTIONARY
        return self # THIS IS REQUIRED FROM iadd()!!
dataset/ETHPy150Open cjlee112/pygr/pygr/mapping.py/Graph.__iadd__/swapped operands of `not in`