@Nullable
  static String getGuardValue(PsiAnnotation annotation) {
    final PsiAnnotationMemberValue psiAnnotationMemberValue = annotation.findAttributeValue("value");
    if (psiAnnotationMemberValue instanceof PsiLiteralExpression) {
      final Object value = ((PsiLiteralExpression)psiAnnotationMemberValue).getValue();
      if (value instanceof String) {
        return resolveItself((String)value, annotation);
      }
    }
    return null;
  }
@Nullable
  static String getGuardValue(PsiAnnotation annotation)