@Nullable
  private static TextRange findSentenceRange(String editorText, int start, int end) {
    int sentenceStart = start;

    while (sentenceStart > 0) {
      if (start - sentenceStart > 1000) return null;
      if (isSentenceEnd(editorText, sentenceStart - 1) || !isNatural(editorText.charAt(sentenceStart - 1))) {
        break;
      }
      sentenceStart--;
    }

    int sentenceEnd = Math.max(0, end - 1);

    while (sentenceEnd < editorText.length()) {
      sentenceEnd++;
      if (sentenceEnd - end > 1000) return null;
      if (isSentenceEnd(editorText, sentenceEnd - 1)) {
        break;
      }
    }

    while (sentenceStart < sentenceEnd && Character.isWhitespace(editorText.charAt(sentenceStart))) {
      sentenceStart++;
    }
    return new TextRange(sentenceStart, sentenceEnd);
  }
@Nullable
  private static TextRange findSentenceRange(String editorText, int start, int end)