docstr: Returns number of the node labels in the generated graphs.
  
  Returns:
      int: The number of node labels.
docstr_tok: ["Returns","number","of","the","node","labels","in","the","generated","graphs",".","Returns",":","int",":","The","number","of","node","labels","."]
code: def num_node_labels(self):
      r"""
      Returns number of the node labels in the generated graphs.
  
      Returns:
          int: The number of node labels.
      """
      # TODO: change to unique as what we did in graph.py
      return max([gen.num_node_labels for gen in self.generators])
  
imports: import copy
  import math
  import types
  import random
  import networkx
  import numpy
  import torch
  import deepsnap
  from deepsnap.graph import Graph
  from deepsnap.hetero_graph import HeteroGraph
  import pdb
  from typing import Dict, List, Union
  import warnings
label_desc: Use image node_id 2 for calling the EnsembleGenerator obj's underlying member method code with example usage: obj.num_node_labels() and returns: max