text: # Copyright (c) Facebook, Inc. and its affiliates.
  #
  # This source code is licensed under the MIT license found in the
  # LICENSE file in the root directory of this source tree.
  
  from fairseq_mod.data.encoders import register_tokenizer
  
  
  @register_tokenizer('nltk')
  class NLTKTokenizer(object):
  
      def __init__(self, source_lang=None, target_lang=None):
          try:
              from nltk.tokenize import word_tokenize
              self.word_tokenize = word_tokenize
          except ImportError:
              raise ImportError('Please install nltk with: pip install nltk')
  
      def encode(self, x: str) -> str:
          return ' '.join(self.word_tokenize(x))
  
      def decode(self, x: str) -> str:
          return x
  