code: @Deprecated
      public int findLastIn(CharSequence value, int fromIndex, boolean findNot) {
          //TODO add strings, optimize, using ICU4C algorithms
          int cp;
          fromIndex -= 1;
          for (; fromIndex >= 0; fromIndex -= UTF16.getCharCount(cp)) {
              cp = UTF16.charAt(value, fromIndex);
              if (contains(cp) != findNot) {
                  break;
              }
          }
          return fromIndex < 0 ? -1 : fromIndex;
      }
docs: Find the last index before fromIndex where the UnicodeSet matches at that index.
  If findNot is true, then reverse the sense of the match: find the last place where the UnicodeSet doesn't match.
  If there is no match, -1 is returned.
  BEFORE index is not in the UnicodeSet.
  @deprecated This API is ICU internal only. Use spanBack instead.
  @hide original deprecated declaration
  @hide draft / provisional / internal are hidden on Android