43     public function getItem($key): CacheItemInterface  argument
45         return current($this->getItems([$key]));  // @phpstan-ignore-line
61         foreach ($keys as $key) {
62             $items[$key] = $this->hasItem($key) ? clone $this->items[$key] : new $itemClass($key);
74     public function hasItem($key): bool  argument
76         $this->isValidKey($key);
78         return isset($this->items[$key]) && $this->items[$key]->isHit();
101     public function deleteItem($key): bool  argument
103         return $this->deleteItems([$key]);
116         foreach ($keys as $key) {
117             unset($this->items[$key]);
169      * @param string $key
173     private function isValidKey($key)  argument
177         if (!is_string($key) || preg_match("#[$invalidCharacters]#", $key)) {
178 …    throw new InvalidArgumentException('The provided key is not valid: ' . var_export($key, true));