code: @Nonnull
      public final Word<I> suffix(int suffixLen) {
          int wordLen = length();
          int startIdx = (suffixLen < 0) ? -suffixLen : (wordLen - suffixLen);
  
          return subWord(startIdx, wordLen);
      }
docs: Retrieves a suffix of the given length. If <code>length</code> is negative, then a suffix consisting of all but
  the first <code>-length</code> symbols is returned.
  
  @param suffixLen
  the length of the suffix (may be negative, see above).
  
  @return the suffix of the given length.