private static @Nullable Pair<String, List<PyRequirement>> getExtraRequires(@NotNull PyExpression extra, @Nullable PyExpression requires) {
    if (extra instanceof PyStringLiteralExpression) {
      final List<String> requiresValue = resolveRequiresValue(requires);

      if (requiresValue != null) {
        return Pair.createNonNull(((PyStringLiteralExpression)extra).getStringValue(),
                                  PyRequirementParser.fromText(StringUtil.join(requiresValue, "\n")));
      }
    }

    return null;
  }
private static @Nullable Pair<String, List<PyRequirement>> getExtraRequires(@NotNull PyExpression extra, @Nullable PyExpression requires)