Question about LpPenalty

[lan2720]

I'm a beginner in deep learning and pylearn2 and meet some knots now.
In pylearn2/costs/tests/test_lp_penalty_cost.py I found some guide to use LpPenalty, but I wonder how to add LpPenalty in my yaml file. Since LpPenalty needs two params LpPenalty(variables=model.get_params(), p=2), but in yaml file how I can use model.get_params() method to get model's params?

Thanks