public function has($key)
    {
        return (isset($this->bag[$key]) || array_key_exists($key, $this->bag));
    }
public function has($key)
    {
        return (isset($this->bag[$key]) || array_key_exists($key, $this->bag));
    }
public function has ( $ key ) { return ( isset ( $ this -> bag [ $ key ] ) || array_key_exists ( $ key , $ this -> bag ) ) ; }
If bag container have given key.

@param  string|int
@return bool
If bag container have given key .