class_docstr: A language model on the 1B words corpus, character level.
  
  Ratio of dev chars (including eos) to dev words (including eos)
  826189 / 159658 = 5.174742; multiply log-ppl by this to compare results.
class_docstr_tok: ["A","language","model","on","the","1B","words","corpus",",","character","level",".","Ratio","of","dev","chars","(","including","eos",")","to","dev","words","(","including","eos",")","826189","\/","159658","=","5.174742",";","multiply","log-ppl","by","this","to","compare","results","."]
code: def vocab_type(self):
      return text_problems.VocabType.CHARACTER
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import os
  import tarfile
  from six.moves import range
  from tensor2tensor.data_generators import generator_utils
  from tensor2tensor.data_generators import problem
  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 1 for calling the LanguagemodelLm1bCharacters obj's underlying member method code with example usage: obj.vocab_type() and returns: text_problems