$self->debug_level( 4 );

    print "Original: ", \$self->debug_level, " Value: ", $self->debug_level, "\n";
    
    my $obj = Something->new( {
      'debug_level' => \$self->debug_level,
    } );
    
    print "Reference: ", $obj->debug_level, " Value: ", ${$obj->debug_level}, "\n";
    
    $self->debug_level( 0 );

    print "After change:\n";
    print "Original: ", \$self->debug_level, " Value: ", $self->debug_level, "\n";
    print "Reference: ", $obj->debug_level, " Value: ", ${$obj->debug_level}, "\n";

##</code><code>##

Original: SCALAR(0xd463da0) Value: 4
Reference: SCALAR(0xd468640) Value: 4
After change:
Original: SCALAR(0xd463da0) Value: 0
Reference: SCALAR(0xd468640) Value: 4

##</code><code>##

  has 'debug_level' => (
    traits => [qw(Getopt)],
    is => 'rw',
    isa => 'Int',
    default => 0,
    cmd_aliases => 'd',
    documentation => 'Debug mode: 0-4; Default: 0;'
  );

##</code><code>##

  has 'debug_level' => (
    is => 'rw',
    isa => 'ScalarRef[Int]',
  );

##</code><code>##

    my $obj = Something->new( {
      # Before:
      #'debug_level' => \$self->debug_level,
      # Now:
      'debug_level' => \$self->{'debug_level'},
    } );