text: #!/usr/bin/env python3
  # Copyright    2021  Xiaomi Corp.        (authors: Fangjun Kuang)
  #
  # See ../../../../LICENSE for clarification regarding multiple authors
  #
  # 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.
  
  """
  This file takes as input a lexicon.txt and output a new lexicon,
  in which each word has a unique pronunciation.
  
  The way to do this is to keep only the first pronunciation of a word
  in lexicon.txt.
  """
  
  
  import argparse
  import logging
  from pathlib import Path
  from typing import List, Tuple
  
  from icefall.lexicon import read_lexicon, write_lexicon
  
  
  def get_args():
      parser = argparse.ArgumentParser()
      parser.add_argument(
          "--lang-dir",
          type=str,
          help="""Input and output directory.
          It should contain a file lexicon.txt.
          This file will generate a new file uniq_lexicon.txt
          in it.
          """,
      )
  
      return parser.parse_args()
  
  
  def filter_multiple_pronunications(
      lexicon: List[Tuple[str, List[str]]]
  ) -> List[Tuple[str, List[str]]]:
      """Remove multiple pronunciations of words from a lexicon.
  
      If a word has more than one pronunciation in the lexicon, only
      the first one is kept, while other pronunciations are removed
      from the lexicon.
  
      Args:
        lexicon:
          The input lexicon, containing a list of (word, [p1, p2, ..., pn]),
          where "p1, p2, ..., pn" are the pronunciations of the "word".
      Returns:
        Return a new lexicon where each word has a unique pronunciation.
      """
      seen = set()
      ans = []
  
      for word, tokens in lexicon:
          if word in seen:
              continue
          seen.add(word)
          ans.append((word, tokens))
      return ans
  
  
  def main():
      args = get_args()
      lang_dir = Path(args.lang_dir)
  
      lexicon_filename = lang_dir / "lexicon.txt"
  
      in_lexicon = read_lexicon(lexicon_filename)
  
      out_lexicon = filter_multiple_pronunications(in_lexicon)
  
      write_lexicon(lang_dir / "uniq_lexicon.txt", out_lexicon)
  
      logging.info(f"Number of entries in lexicon.txt: {len(in_lexicon)}")
      logging.info(f"Number of entries in uniq_lexicon.txt: {len(out_lexicon)}")
  
  
  if __name__ == "__main__":
      formatter = (
          "%(asctime)s %(levelname)s [%(filename)s:%(lineno)d] %(message)s"
      )
  
      logging.basicConfig(format=formatter, level=logging.INFO)
  
      main()
  