class_docstr: Abstract InputPipeline class. All input pipelines must inherit from this.
  An InputPipeline defines how data is read, parsed, and separated into
  features and labels.
  
  Params:
    shuffle: If true, shuffle the data.
    num_epochs: Number of times to iterate through the dataset. If None,
      iterate forever.
class_docstr_tok: ["Abstract","InputPipeline","class",".","All","input","pipelines","must","inherit","from","this",".","An","InputPipeline","defines","how","data","is","read",",","parsed",",","and","separated","into","features","and","labels",".","Params",":","shuffle",":","If","true",",","shuffle","the","data",".","num_epochs",":","Number","of","times","to","iterate","through","the","dataset",".","If","None",",","iterate","forever","."]
docstr: Defines the labels that this input pipeline provides. Returns
  a set of strings.
docstr_tok: ["Defines","the","labels","that","this","input","pipeline","provides",".","Returns","a","set","of","strings","."]
code: def label_keys(self):
      """Defines the labels that this input pipeline provides. Returns
      a set of strings.
      """
      return set()
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from __future__ import unicode_literals
  import abc
  import sys
  import six
  import tensorflow
  from tensorflow.contrib.slim.python.slim.data import tfexample_decoder
  from seq2seq.configurable import Configurable
  from seq2seq.data import split_tokens_decoder, parallel_data_provider
  from seq2seq.data.sequence_example_decoder import TFSEquenceExampleDecoder
label_desc: Use image node_id 5 for calling the InputPipeline obj's underlying member method code with example usage: obj.label_keys() and returns: set