@Override
    public void visitPyStringLiteralExpression(@NotNull PyStringLiteralExpression node) {
      String value = node.getStringValue();
      PsiFile file = node.getContainingFile(); // can't cache this in the instance, alas
      if (file == null) return;
      boolean default_bytes = false;
      if (file instanceof PyFile pyfile) {
        default_bytes = (!UNICODE_LITERALS.requiredAt(pyfile.getLanguageLevel()) &&
                         !pyfile.hasImportFromFuture(UNICODE_LITERALS)
        );
      }

      final String charsetString = PythonFileType.getCharsetFromEncodingDeclaration(file);
      try {
        if (charsetString != null && !Charset.forName(charsetString).equals(StandardCharsets.US_ASCII))
          default_bytes = false;
      } catch (UnsupportedCharsetException | IllegalCharsetNameException ignored) {}

      boolean hasNonAscii = false;

      int length = value.length();
      char c = 0;
      for (int i = 0; i < length; ++i) {
        c = value.charAt(i);
        if (((int) c) > 255) {
          hasNonAscii = true;
          break;
        }
      }

      char first_char = Character.toLowerCase(node.getText().charAt(0));
      boolean isByte = first_char == 'b' || (default_bytes && first_char != 'u');

      if (hasNonAscii && isByte) {
        registerProblem(node, PyPsiBundle.message("INSP.byte.literal.contains.illegal.characters"));
      }
    }
@Override
    public void visitPyStringLiteralExpression(@NotNull PyStringLiteralExpression node)