@Nullable PsiExpression getFormatString() {
      if (!(myExpression.getParent() instanceof PsiExpressionList list) ||
          !(list.getParent() instanceof PsiCallExpression call)) {
        return null;
      }
      FormatDecode.FormatArgument argument = FormatDecode.FormatArgument.extract(call, List.of(), List.of(), true);
      if (argument == null) return null;
      return argument.getExpression();
    }
@Nullable PsiExpression getFormatString()