#!/usr/bin/perl
use Foo;
my $foo = Foo->new qw( Bar );
for ( @{ $foo->{'submodules'} } ) {
    print $_->details->{'name'} 
      . " is a "
      . $_->details->{'job'}
      . $/;
}
# prints: Can't locate object method "details" via package "Bar" 
# (perhaps you forgot to load "Bar"?)