Stash\Pool::getItem PHP Method

    public function getItem($key)
    {
        $keyString = trim($key, '/');
        $key = explode('/', $keyString);
        $namespace = empty($this->namespace) ? 'stash_default' : $this->namespace;
        array_unshift($key, $namespace);
        foreach ($key as $node) {
            if (!isset($node[1]) && strlen($node) < 1) {
                throw new InvalidArgumentException('Invalid or Empty Node passed to getItem constructor.');
            }
        }
        /** @var ItemInterface $item */
        $item = new $this->itemClass();
        $item->setPool($this);
        $item->setKey($key, $namespace);
        if ($this->isDisabled) {
            $item->disable();
        }
        if (isset($this->logger)) {
            $item->setLogger($this->logger);
        }
        return $item;
    }

 public function deleteFromCache(string $platform, string $pageName)
 {
     $item = $this->pool->getItem($platform . "/" . $pageName);
     $item->clear();
     $item = $this->pool->getItem("common/" . $pageName);
     $item->clear();
 }