code: def __check_spaces(sentence):
      
      # We have to run the process multiple times:
      #   Once to search for all spaces, and check if there are adjoining spaces;
      #   The second time to check for 2 spaces after sentence-ending characters such as . and ! and ?
  
      if sentence is not None:
  
          words = sentence.split()
  
          new_sentence = ''
  
          for (i, word) in enumerate(words):
  
              if word[-1] in set('.!?'):
                  word += ' '
              new_word = ''.join(word)
              new_sentence += ' ' + new_word
  
          # remove any trailing whitespace
          new_sentence = new_sentence.strip()
  
      return new_sentence
docs: Here we check to see that we have the correct number of spaces in the correct locations.
  
      :param _sentence:
      :return: