public static void assertValidSeparators(@NotNull CharSequence s) {
    char[] chars = CharArrayUtil.fromSequenceWithoutCopying(s);
    int slashRIndex = -1;

    if (chars != null) {
      for (int i = 0, len = s.length(); i < len; ++i) {
        if (chars[i] == '\r') {
          slashRIndex = i;
          break;
        }
      }
    }
    else {
      for (int i = 0, len = s.length(); i < len; i++) {
        if (s.charAt(i) == '\r') {
          slashRIndex = i;
          break;
        }
      }
    }

    if (slashRIndex != -1) {
      String context =
        String.valueOf(last(s.subSequence(0, slashRIndex), 10, true)) + first(s.subSequence(slashRIndex, s.length()), 10, true);
      context = escapeStringCharacters(context);
      throw new AssertionError("Wrong line separators: '" + context + "' at offset " + slashRIndex);
    }
  }
public static void assertValidSeparators(@NotNull CharSequence s)