package MyClass;
sub new {
    my ($class, %args) = @_;
    return bless \%args => $class;
}
sub add {
    my ($self, %args) = @_;
    while (my ($k, $v) = each %args) {
        $self->{$k} = $v;
    }
    return $self;
}
sub greet {}

package main;
my $obj = MyClass->new(message => "Guten Morgen", nachname => "Wall", vorname => "Larry");
$obj->add(bla => 'blubb', foo => 'bar');
use DDP; p $obj;
__END__
MyClass  {
    public methods (3) : add, greet, new
    private methods (0)
    internals: {
        bla        "blubb",
        foo        "bar",
        message    "Guten Morgen",
        nachname   "Wall",
        vorname    "Larry"
    }
}