code: def walk_generator(self):
      if self.walkpath_files is not None:
          for i in self.walk_from_files():
              yield i
      else:
          for i in self.walk_from_graph():
              yield i
  
imports: from __future__ import division
  from __future__ import absolute_import
  from __future__ import print_function
  import time
  import io
  import os
  import numpy
  import paddle
  from pgl.utils.logger import log
  from pgl.sample import node2vec_sample
  from pgl.sample import deepwalk_sample
  from pgl.sample import alias_sample
  from pgl.graph_kernel import skip_gram_gen_pair
  from pgl.graph_kernel import alias_sample_build_table
  from pgl.utils import mp_reader
label_desc: Use image node_id 4 for calling the DeepwalkReader obj's underlying member method code with example usage: obj.walk_generator() without return types