sub can {
    my ( $proto, $method ) = @_;

    my ($callpack) = caller(0);
    my $class = ref $proto || $proto;
    if ( my $coderef = $proto->SUPER::can($method) ) {
        return $coderef if 'can' eq $method;

        my $code_package = $package_for->($coderef);
        if ( 
            $class->isa($code_package) 
            && 
            ('_' ne substr($method, 0, 1) || $callpack->isa($code_package))
          )     
        {           
            return $coderef;
        } 
    }   
    return; 
}