my $parameter_config = {
        mandatory  => {type    => 'boolean',
                       default => 0,
                       valid   => 0},
                       };

sub parameter_config { $parameter_config };

sub valid_parameter {
    my $class = shift;

    my @param = @_;
    foreach (@param) {
        my $param_config = $class->parameter_config->{$_};
        if ($param_config) {
            $param_config->{valid} = 1;
        } else {
            die "Parameter $_ not known";
        }
    }
    return 1;
}


##</code><code>##


Integer->valid_parameter(qw(mandatory));