public function delete($key)
    {
        if (isset($this->items[$key])) {
            unset($this->items[$key]);
        }
        return $this;
    }
public function delete($key)
    {
        if (isset($this->items[$key])) {
            unset($this->items[$key]);
        }
        return $this;
    }
Delete.

@param string $key
@return $this