Creating a hash out of multiple XML attributes in an elment

[perlvroom]

Ok, the following script does what i need, but i was hoping someone could school me on how to do this more effeciently:

use XML::Twig;

  my $t= XML::Twig->new( twig_handlers => 
                           {   'settings' => \&file,
                                                }
                      
 )  ->parsefile( 'sample.xml');

sub file{
    my($t, $settings)=@_;
    
    foreach($settings->att('key')){
    if($settings->att('key') eq 'a'){
        $a = $settings->att('value');
        
    }
    if($settings->att('key') eq 'b'){
        $b = $settings->att('value');    
    }
    }
}

XML snippet:
<settings key="a" value="1"/>
<settings key="b" value="2"/>
The goal is to declare the "key" attribute as a variable with it's value equal to the "value" attribute in the same element, for all "settings" elements.