#!/usr/bin/env perl
{
    package FishTaco::Topping;
    use Moo;
}
{
    package FishTaco;
    use Moo;
    use MooX::HandlesVia;
    use Types::Standard qw( ArrayRef InstanceOf );
    has _toppings =>
        is => "rw",
        isa => ArrayRef[ InstanceOf['FishTaco::Topping'] ],
        default => sub { [] },
        handles_via => "Array",
        handles => {
            add_topping => "push",
            toppings => "elements",
        };
}
use strictures;
use Path::Tiny;
use Scalar::Util "blessed";

my $ft = FishTaco->new;
$ft->add_topping( FishTaco::Topping->new ); # Sure.
$ft->add_topping( path("/") ); # Wrong object type.
$ft->add_topping( "OHAI" ); # Not even an object.

print blessed($_) || "[n/a]", $/ for $ft->toppings;

__END__
FishTaco::Topping
Path::Tiny
[n/a]