@Override
      public void visitElement(@NotNull PsiElement element) {
        if (element == root) {
          if (element instanceof JsonObject) {
            final JsonProperty schemaProp = ((JsonObject)element).findProperty("$schema");
            if (schemaProp != null) {
              doCheck(schemaProp.getValue());
            }
          }
        }
        super.visitElement(element);
      }
@Override
      public void visitElement(@NotNull PsiElement element)