# MyClass.pm
package MyClass;
use BaseClass;   # load the base class
use SubClass;    # load the sub class (which now extends BaseClass)

our @ISA = qw(BaseClass); # have all BaseClass methods work on MyClass
1;

##</code><code>##

# BaseClass.pm
package BaseClass;
use Moose;

sub get_subclass_object {
    return SubClass->new;
}
1;

##</code><code>##

# SubClass.pm
package SubClass;
use Moose;

extends 'BaseClass';

1;