code: def calc(self, count_in_class, total_count):
      ctr = (count_in_class + self.prior_num) / float(
          total_count + self.prior_denom
      )
      return (ctr + self.shift) * self.scale
  
label_desc: Use image node_id 2 for calling the catboost_model_ctr obj's underlying member method code with example usage: obj.calc(count_in_class, total_count) and returns: unknown