class_docstr: Tracks nodes and edges of a directed graph and supports basic operations on them.
class_docstr_tok: ["Tracks","nodes","and","edges","of","a","directed","graph","and","supports","basic","operations","on","them","."]
code: def add_node(self, node):
      id = self.id(node)
      # assert(id not in self.nodes)
      self.nodes[id] = node
  
imports: from __future__ import absolute_import, division, print_function
  import os
  import re
  from random import getrandbits
  import inspect
  import numpy
  import html
label_desc: Use image node_id 3 for calling the Graph obj's underlying member method code with example usage: obj.add_node(node) without return types