class_docstr: Seq2Edits for grammatical error correction.
class_docstr_tok: ["Seq2Edits","for","grammatical","error","correction","."]
code: def example_reading_spec(self):
      data_fields, _ = super(Seq2editsGec, self).example_reading_spec()
      data_fields["targets_start_token"] = tf.VarLenFeature(tf.int64)
      data_fields["targets_end_token"] = tf.VarLenFeature(tf.int64)
      data_fields["targets_error_tag"] = tf.VarLenFeature(tf.int64)
      return data_fields, None
  
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.layers import modalities
  from tensor2tensor.utils import registry
  import tensorflow.compat.v1
label_desc: Use image node_id 7 for calling the Seq2editsGec obj's underlying member method code with example usage: obj.example_reading_spec() and returns: data_fields,  None