#!/usr/bin/env perl6
use v6;

class MyClass {
    has $.length is rw;
    has $.height is rw;
    has $.color is rw;

    method my_method ( Array $list, Hash $opt? ) {
        if defined $opt {
            for %$opt.keys -> $key {
                when $key eq 'length' {
                    $!length = $opt{$key};
                }
                when $key eq 'height' {
                    $!height = $opt{$key};
                }
                when $key eq 'color' {
                    $!color = $opt{$key};
                }
            }
        }
    }
}

my $n = MyClass.new();
$n.my_method( [ 1, 2, 3 ], { length => 10, height => 6, color => 'green' });
say $n.perl;