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

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