Inject/Injector.php
public function offsetExists($offset)
    {
        return isset($this->objects[$offset]) || isset($this->caches[$offset]) || isset($this->data[$offset]);
    }
public function offsetExists($offset)
    {
        return isset($this->objects[$offset]) || isset($this->caches[$offset]) || isset($this->data[$offset]);
    }
** implement methods of ArrayAccess ***