$valobj->value = undef;

##</code><code>##

    $valobj->value = '';

##</code><code>##

    sub value : lvalue {
        my $this = shift;
        $this->{VALUE};
    }

##</code><code>##

    sub value {
        my ($self, $value) = @_;
        if (defined $value) {
            $self->{value} = $value;
        };
    };
    $valobj->value(undef);