@since 5.4.0

@return bool
549182
public function overridePrince() {
		$use_hooks = true;
		if ( ! defined( 'DOCRAPTOR_API_KEY' ) ) {
			// No API key
			$use_hooks = false;
		}
		$plugin = 'pressbooks-docraptor/pressbooks-docraptor.php';
		if ( file_exists( WP_PLUGIN_DIR . "/{$plugin}" ) && is_plugin_active( $plugin ) ) {
			// The old, deprecated plugin is active
			$use_hooks = false;
		}
		return $use_hooks;
	}
57657
public function isTracking()
    {
        if ($this->isTracking === false) {
            return false;
        }

        if (!$this->resqueInstance->redis->exists((string)$this)) {
            $this->isTracking = false;
            return false;
        }

        $this->isTracking = true;
        return true;
    }
298630
protected function isVersioned()
    {
        if (!class_exists(Versioned::class)) {
            return false;
        }
        /** @var Versioned|DataObject $singleton */
        $singleton = DataObject::singleton($this->getBaseClass());
        return $singleton->hasExtension(Versioned::class) && $singleton->hasStages();
    }
385782
public function hasLoop()
	{
		foreach( $this->getNodes() as $node )
			if( $this->isLoop( $node ) )
				return true;
		return false;
	}
241592
public function valid()
    {
        if (!isset($this->rs)) {
            $this->doRs();
        }

        return in_array($this->currentKey, array_keys($this->rs));
    }
999058
public function valid()
    {
        // initialize/refresh cursor
        if ($this->cursor != 0 && !isset($this->elements[$this->index])) {
            $this->scan();
        }

        return isset($this->elements[$this->index]);
    }
52911
public function valid()
    {
        if (is_null($this->current)) {
            return true;
        }
        if ($this->current instanceof RecursiveLeafInterface) {
            return $this->current->valid();
        }

        return false;
    }
54244
public function canEmbed():bool
    {
        return (
            !Craft::$app->getRequest()->getIsAjax() &&
            !Craft::$app->getRequest()->getIsConsoleRequest() &&
            !Craft::$app->getRequest()->getIsCpRequest() &&
            !Craft::$app->getRequest()->getIsLivePreview() &&
            !Craft::$app->getUser()->getIsGuest() &&
            (Craft::$app->getUser()->getIsAdmin() || Craft::$app->getUser()->checkPermission('accessCp'))
        );
    }
813124
public function hasOnUpdate()
    {
        $database = $this->getTable()->getDatabase();
        if($database instanceof Database &&
               $this->onUpdate === $database->getPlatform()->getDefaultFKOnUpdateBehavior()) {
          return false;
        }

        return ($this->onUpdate !== self::NONE);
    }
1138809
public function valid()
    {
        return isset($this->base['value'][$this->position]) && is_array($this->base['value'][$this->position]);
    }
813190
public function close()
    {
        if ($this->closed) {
            return false;
        }
        $this->closed = true;
        if ($this->fdCacheKey !== null) {
            FileSystem::$fdCache->invalidate($this->fdCacheKey);
        }
        if ($this->fd === null) {
            return false;
        }

        if (!FileSystem::$supported) {
            fclose($this->fd);
            return false;
        }
        $r = eio_close($this->fd, EIO_PRI_MAX);
        $this->fd = null;
        return $r;
    }
84325
public function valid()
    {

        if ($this->container['response'] === null) {
            return false;
        }
        $allowedValues = $this->getResponseAllowableValues();
        if (!in_array($this->container['response'], $allowedValues)) {
            return false;
        }
        return true;
    }
1215974
public function valid()
    {
        if (!isset($this->keys[$this->position])) {
            return false;
        }

        $currentKey = $this->keys[$this->position];

        return isset($this->items[$currentKey]);
    }
975841
public function valid()
    {
        if($this->folderList == null){
            $this->folderList = $this->listFolder();
        }
        return is_array($this->folderList) && isset($this->folderList[$this->key]);
    }
1080523
public function valid()
    {
        //echo 'v';
        $v = $this->currentIterator->valid();
        if (!$v) {
            do {
                $this->iterators->next();
                if ($this->iterators->valid()) {
                    $this->currentIterator = $this->iterators->current();
                    $this->currentIterator->rewind();
                }
            } while ($this->iterators->valid() && !$this->currentIterator->valid());

            if (!$this->currentIterator->valid()) {
                return false;
            } else {
                return true;
            }
        }

        return $v;
    }
493499
public function canHandle(): bool
    {
        if ($this->table !== 'pages') {
            return false;
        }

        if (!$this->backendUser->isAdmin()) {
            return false;
        }

        /** @var $rootPageResolver RootPageResolver */
        $rootPageResolver = GeneralUtility::makeInstance(RootPageResolver::class);
        return $rootPageResolver->getIsRootPageId((int)$this->identifier);
    }
105607
public function hasFilters() {
		foreach ($this->columns as $col) {
			if ($col->hasFilters() === true) {
				return true;
			}
		}

		return false;
	}