How to disable a single menu item in Perl/Tk menubar?

The following code creates a menu list called "User Selection" with four menu items: "Save", "Save As", "Load, and "Load From":

my $userselectedmenuitems = [
                      [ 'command' , 'Save', -command => \&saveUserSelection ]
                      [ 'command' , 'Save As', -command => \&saveUserSelectionAs ]
                      [ 'command' , 'Load', -command => \&loadSelectionsFromDefaultXMLFile ]
                      [ 'command' , 'Load From', -command => \&loadSelectionsFromUserSpecifiedXMLFile ] ;
my $userselectedmenu = $menubar->cascade (
                             -label => 'User Selection',
                             -tearoff => 0,
                             -menuitems => $userselectedmenuitems,
                      ) ;

Now, the following code will cause the entire menu list to be disabled:

$userselectedmenu->configure(-state => 'disable');

However, that's not what I want. I want to disable only one entry in the list (specifically the "Save" entry). How do I do that?

I saw online that many examples refer to the function "entryconfigure". However, when I run this code:

$userselectedmenu->entryconfigure('Save', -state => 'disable');

I get the following error message:

Can't locate object method "entryconfigure" via package "Tk::Menu::Cascade" at [line number]

Disclaimer: I apologize if this code needs some massaging to be reproducible, I have to transcribe code to this computer by hand.

You first need entrycget to get the menu, then you can use entryconfigure to disable its item:

$menubar->entrycget('User Selection', '-menu')
        ->entryconfigure('Save', -state => 'disabled');