code: def log_prob(
      self, scores: torch.Tensor, action: torch.Tensor
  ) -> torch.Tensor:
      raise NotImplementedError
  
file_path: ReAgent/reagent/gym/policies/samplers/top_k_sampler.py
imports: import reagent.core.types
  import torch
  from reagent.gym.types import Sampler
label_desc: Use image node_id 3 for calling the TopKSampler obj's underlying member method code with example usage: obj.log_prob(scores, action) without return types