class_docstr: A penalty that does not penalize.
class_docstr_tok: ["A","penalty","that","does","not","penalize","."]
code: def deriv2(self, params):
      # returns diagonal of hessian
      return np.zeros(params.shape[0])
  
imports: import numpy
label_desc: Use image node_id 4 for calling the NonePenalty obj's underlying member method code with example usage: obj.deriv2(params) and returns: np