@Override
    @NotNull
    public PsiElementVisitor buildVisitor(@NotNull final ProblemsHolder holder, boolean isOnTheFly) {
        if (!(holder.getFile() instanceof XmlFile)) return PsiElementVisitor.EMPTY_VISITOR;
        return new MyVisitor(holder);
    }
@Override
    @NotNull
    public PsiElementVisitor buildVisitor(@NotNull final ProblemsHolder holder, boolean isOnTheFly)