sub deepcopy{
    my $this = shift;
    if (not ref $this){
	$this;
    }
    elsif (ref $this eq "ARRAY") {
	[map deepcopy($_), @$this];
    }
    elsif (ref $this eq "HASH"){
	scalar  { map { $_ => deepcopy($this->{$_}) } keys %$this };
    }
    else { die "what type is $_?"}
}