code: def pairwise_distance(self, query_emb, ref_emb):
      query_var = torch.var(query_emb, dim=1)
      query_ref_var = torch.var(query_emb - ref_emb, dim=1)
      return query_ref_var / query_var
  
imports: import torch
  from .base_distance import BaseDistance
label_desc: Use image node_id 3 for calling the SNRDistance obj's underlying member method code with example usage: obj.pairwise_distance(query_emb, ref_emb) and returns: unknown