@Override
  protected @NotNull IElementType getUnicodeEscapeSequenceType() {
    int start = myStart + 2;
    while (start < myEnd && myBuffer.charAt(start) == 'u') start++;
    if (start + 3 >= myEnd) return StringEscapesTokenTypes.INVALID_UNICODE_ESCAPE_TOKEN;
    if (!StringUtil.isHexDigit(myBuffer.charAt(start)) ||
        !StringUtil.isHexDigit(myBuffer.charAt(start + 1)) ||
        !StringUtil.isHexDigit(myBuffer.charAt(start + 2)) ||
        !StringUtil.isHexDigit(myBuffer.charAt(start + 3))) {
      return StringEscapesTokenTypes.INVALID_UNICODE_ESCAPE_TOKEN;
    }
    return StringEscapesTokenTypes.VALID_STRING_ESCAPE_TOKEN;
  }
@Override
  protected @NotNull IElementType getUnicodeEscapeSequenceType()