class_docstr: Allows training a variant of Text2textTmpdirTokens that supports copying.
  
  Handling the case where the input contains OOV tokens. Store a temporary vocab
  ID for source OOV, so that the decoder can directly copy from the input.
  Uses TokenTextEncoderOov as the vocab encoder.
class_docstr_tok: ["Allows","training","a","variant","of","Text2textTmpdirTokens","that","supports","copying",".","Handling","the","case","where","the","input","contains","OOV","tokens",".","Store","a","temporary","vocab","ID","for","source","OOV",",","so","that","the","decoder","can","directly","copy","from","the","input",".","Uses","TokenTextEncoderOov","as","the","vocab","encoder","."]
code: def example_reading_spec(self):
      data_fields = {
          "inputs": tf.VarLenFeature(tf.int64),
          "inputs_extend": tf.VarLenFeature(tf.int64),
          "targets": tf.VarLenFeature(tf.int64),
          "targets_extend": tf.VarLenFeature(tf.int64),
      }
      data_items_to_decoders = None
      return (data_fields, data_items_to_decoders)
  
file_path: tensor2tensor/tensor2tensor/data_generators/pointer_generator_word.py
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import os
  from tensor2tensor.data_generators import text_encoder
  from tensor2tensor.data_generators import text_problems
  from tensor2tensor.utils import registry
  import tensorflow.compat.v1
label_desc: Use image node_id 4 for calling the Text2textCopyableTokens obj's underlying member method code with example usage: obj.example_reading_spec() and returns: data_fields,  data_items_to_decoders