class_docstr: Pop is an fundamental model that always recommend the most popular item.
code: def calculate_loss(self, interaction):
      item = interaction[self.ITEM_ID]
      self.item_cnt[item, :] = self.item_cnt[item, :] + 1
  
      self.max_cnt = torch.max(self.item_cnt, dim=0)[0]
  
      return torch.nn.Parameter(torch.zeros(1)).to(self.device)
  
file_path: RecBole/recbole/model/general_recommender/pop.py
imports: import torch
  from recbole.model.abstract_recommender import GeneralRecommender
  from recbole.utils import InputType, ModelType
label_desc: Use image node_id 3 for calling the Pop obj's underlying member method code with example usage: obj.calculate_loss(interaction) and returns: torch