public function asNull(): Primitive\NullType
    {
        if (!$this->_element instanceof Primitive\NullType) {
            throw new \UnexpectedValueException(
                $this->_generateExceptionMessage(Element::TYPE_NULL));
        }
        return $this->_element;
    }
public function asNull(): Primitive\NullType
    {
        if (!$this->_element instanceof Primitive\NullType) {
            throw new \UnexpectedValueException(
                $this->_generateExceptionMessage(Element::TYPE_NULL));
        }
        return $this->_element;
    }
public function asNull ( ) : Primitive \ NullType { if ( ! $ this -> _element instanceof Primitive \ NullType ) { throw new \ UnexpectedValueException ( $ this -> _generateExceptionMessage ( Element :: TYPE_NULL ) ) ; } return $ this -> _element ; }
Get the wrapped element as a null type.

@throws \UnexpectedValueException If the element is not a null
@return \ASN1\Type\Primitive\NullType
Get the wrapped element as a null type .