public function issetItem($key) {
		if (is_array($key)) {
			$key = $this->arrayHashFunction($key);
		}
		
		return isset($this->_data[$key]);
	}
public function issetItem($key) {
		if (is_array($key)) {
			$key = $this->arrayHashFunction($key);
		}
		
		return isset($this->_data[$key]);
	}
public function issetItem ( $ key ) { if ( is_array ( $ key ) ) { $ key = $ this -> arrayHashFunction ( $ key ) ; } return isset ( $ this -> _data [ $ key ] ) ; }
Item exists check

@param  string | int $key
@return bool
Item exists check