您可以从CodeIgniter中的另一个模型中访问模型吗？

I am writing a webapp using CodeIgniter that requires authentication. I created a model which handles all my authentication. However, I can't find a way to access this authentication model from inside another model. Is there a way to access a model from inside another mode, or a better way to handle authentication inside CodeIgniter?I am writing a webapp using CodeIgniter that re