public function exists(string $object) : bool
    {
        return (!empty($this->registry) && isset($this->registry[$object]));
    }
public function exists(string $object) : bool
    {
        return (!empty($this->registry) && isset($this->registry[$object]));
    }
public function exists ( string $ object ) : bool { return ( ! empty ( $ this -> registry ) && isset ( $ this -> registry [ $ object ] ) ) ; }
determines if an object exists in the registry

@param string $object
@return boolean
determines if an object exists in the registry