public function expectImplicit($expectedTag = null): ImplicitTagging
    {
        $el = $this;
        if (!$el instanceof ImplicitTagging) {
            throw new \UnexpectedValueException(
                "Element doesn't implement implicit tagging.");
        }
        if (isset($expectedTag)) {
            $el->expectTagged($expectedTag);
        }
        return $el;
    }
public function expectImplicit($expectedTag = null): ImplicitTagging
    {
        $el = $this;
        if (!$el instanceof ImplicitTagging) {
            throw new \UnexpectedValueException(
                "Element doesn't implement implicit tagging.");
        }
        if (isset($expectedTag)) {
            $el->expectTagged($expectedTag);
        }
        return $el;
    }
public function expectImplicit ( $ expectedTag = null ) : ImplicitTagging { $ el = $ this ; if ( ! $ el instanceof ImplicitTagging ) { throw new \ UnexpectedValueException ( "Element doesn't implement implicit tagging." ) ; } if ( isset ( $ expectedTag ) ) { $ el -> expectTagged ( $ expectedTag ) ; } return $ el ; }
Check whether element supports implicit tagging.

@param int|null $expectedTag Optional outer tag expectation
@throws \UnexpectedValueException If expectation fails
@return ImplicitTagging
Check whether element supports implicit tagging .