code: def __call__(self):
      generator = self.pair_generate
  
      for src, pos, negs in generator():
          dst = np.concatenate([pos, negs], 1)
          yield src, dst
  
imports: from __future__ import division
  from __future__ import absolute_import
  from __future__ import print_function
  import time
  import io
  import os
  import numpy
  import random
  from pgl.utils.logger import log
  from pgl.sample import metapath_randomwalk
  from pgl.graph_kernel import skip_gram_gen_pair
  from pgl.graph_kernel import alias_sample_build_table
  from utils import load_config
  from graph import m2vGraph
  import mp_reader
label_desc: Use image node_id 2 for calling the DataGenerator obj's underlying member method code with example usage: obj.__call__() without return types