protected function _to($name)
    {
        if ($name == 'to_c') {
            if (count($this) != 1) {
                throw new \RuntimeException(
                    'Cannot converting \Malenki\Bah\S object having length '
                    .'not equal to one to C object.'
                );
            }

            return new C($this->value);
        }

        if ($name == 'to_n') {
            if(!is_numeric($this->value)){
                throw new \RuntimeException(
                    'Cannot converting \Malenki\Bah\S object to \Malenki\Bah\N'
                   .' object, because no numeric value were found inside it!'
                );
            }

            return new N((double) $this->value);
        }
    }