class_docstr: Parsing.
class_docstr_tok: ["Parsing","."]
code: def inputs_target_vocab_size(self):
      return 2**9
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import os
  from tensor2tensor.data_generators import problem
  from tensor2tensor.data_generators import text_encoder
  from tensor2tensor.layers import modalities
  from tensor2tensor.utils import registry
  import tensorflow.compat.v1
label_desc: Use image node_id 2 for calling the ParsingEnglishPtb16k obj's underlying member method code with example usage: obj.inputs_target_vocab_size() and returns: unknown