code: private String fillSentenceWithSpaces(List<String> sentence) {
          sentenceWithSpaces.clear();
  
          //We don't need to do this process if the sentence received is a single word.
          if (sentence.size() > 1) {
              //We fill with normal spaces first, we can do this with confidence because "fitsInSentence"
              //already takes these spaces into account.
              for (String word : sentence) {
                  sentenceWithSpaces.add(word);
                  sentenceWithSpaces.add(NORMAL_SPACE);
              }
  
              //Filling sentence with thin spaces.
              while (fitsInSentence(HAIR_SPACE, sentenceWithSpaces, false)) {
                  //We remove 2 from the sentence size because we need to make sure we are not adding
                  //spaces to the end of the line.
                  sentenceWithSpaces.add(getRandomNumber(sentenceWithSpaces.size() - 2), HAIR_SPACE);
              }
          }
  
          return getSentenceFromList(sentenceWithSpaces, false);
      }
docs: Fills sentence with appropriate amount of spaces.
  
  @param sentence Sentence we'll use to build the sentence with additional spaces
  @return String with spaces.