text: # Copyright (c) 2021, NVIDIA CORPORATION.  All rights reserved.
  # Copyright 2015 and onwards Google, Inc.
  #
  # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at
  #
  #     http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  
  from nemo_text_processing.inverse_text_normalization.graph_utils import (
      NEMO_CHAR,
      NEMO_NOT_QUOTE,
      GraphFst,
      delete_space,
  )
  
  try:
      import pynini
      from pynini.lib import pynutil
  
      PYNINI_AVAILABLE = True
  except (ModuleNotFoundError, ImportError):
      PYNINI_AVAILABLE = False
  
  
  class PunctuationFst(GraphFst):
      """
      Finite state transducer for classifying punctuation
          e.g. tokens { name: "a" } tokens { name: "," pause_length: "PAUSE_MEDIUM phrase_break: true type: PUNCT" }
              -> a ,
      """
  
      def __init__(self):
          super().__init__(name="punctuation", kind="verbalize")
          char = (
              pynutil.delete("name:")
              + delete_space
              + pynutil.delete("\"")
              + pynini.closure(NEMO_NOT_QUOTE, 1)
              + pynutil.delete("\" pause_length")
              + pynutil.delete(pynini.closure(NEMO_CHAR - "}"))
          )
          self.fst = char.optimize()
  