# Based on: http://perldoc.perl.org/perlobj.html
use strict;
use warnings;
use parent;
use 5.014;

package A;
  sub new {
      return bless {}, shift;
  }
  sub speak {
        say 'A::speak: entered';
      my $self = shift;
      # $self->SUPER::speak();
      say 'A';
        say 'A::speak: leaving';
  }
package B;
  use parent -norequire, 'A';
  sub speak {
        say 'B::speak: entered';
      my $self = shift;
      $self->SUPER::speak();
      say 'B';
        say 'B::speak: leaving';
  }
package C;
  use parent -norequire, 'B';
  sub speak {
          say 'C::speak: entered';
      my $self = shift;
      $self->SUPER::speak();
      say 'C';
        say 'C::speak: leaving';
  }
  my $c = C->new();
  say 'calling C::speak';
  $c->speak();
  say 'returned from C::speak';
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