Look at this code below

My Parent class has two methods namely 'add' and 'subtract'. I have a problem with my 'add' ( given inside the methodmaker). It is not taking the two arguments passed to the 'add' method. See my child Class. It has got a method 'subtract' which is working fine. But when i hav the same method within a MethorMaker, I get some errors like :

Use of uninitialized value in addition (+) at Parent.pm line 17.
Use of uninitialized value in addition (+) at Parent.pm line 17.
[download]

 package Parent;
 use strict;
 use warnings;
 use Carp;
 use Data::Dumper;
 
 use Class::MethodMaker
 get_set => [ 
              { -read_cb => sub {  ## THIS ONE IS NOT WORKING ........
+.                                
            my ($self,$val1,$val2) = shift;
                        $self->{val1} = $val1;
                        $self->{val2} = $val2;
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my $out =  $self->{val1} + $self->{val2};
              return $out;
                         }
             },'add',
             { -read_cb => sub {
                                  $_[1] - 1;
                               }
             },'subtract'
            ],
 new => 'new';
1;



# Child Class .............

 package Child;

 use Data::Dumper;
 use Parent;

 my (%val1,%val2);
 sub new {

  bless [ ] => shift;

 }

 sub subtract {
    $self = shift;
    $val1{$self}=shift;
    $val2{$self}=shift;
    return $val1{$self}-$val2{$self};
 }

 $myobj = Child->new();
 $subobj=$myobj->subtract(34,31); # this method s working 
 print Dumper $subobj;


 $pObj = Parent->new(); # This is not working 
 $pObj->add(100,3);
 print Dumper $pObj;

 $pObj=Parent->subtract(100); # subtracts 1 from 100 .
 print Dumper $pObj;
[download]

Please tell me wats happening in the add() method in the Parent Class ..
Anything to do with Operating Overloading ????

Thanks in Advance and awaiting your reply, Vishi