public function has($key) {
		$this->check();
		$data = $this->readData();
		return isset($data[$key]);
	}
public function has($key) {
		$this->check();
		$data = $this->readData();
		return isset($data[$key]);
	}
public function has ( $ key ) { $ this -> check ( ) ; $ data = $ this -> readData ( ) ; return isset ( $ data [ $ key ] ) ; }
Check if storage has given key
@return bool
Check if storage has given key