package NewBase;
use strict;

sub new {
   my $class = shift;
   my $self  = {};
   bless $self, $class;
   $self;
}

# other methods

package BaseClass;
use strict;
use base qw(NewBase);

sub bar {
   return Foo->new;
}

package Foo;
use strict;
use base qw(NewBase);