class_docstr: Circle loss for pairwise labels only.
  
  Args:
  m:  The relaxation factor that controls the radious of the decision boundary.
  gamma: The scale factor that determines the largest scale of each similarity score.
  
  According to the paper, the suggested default values of m and gamma are:
  
  Face Recognition: m = 0.25, gamma = 256
  Person Reidentification: m = 0.25, gamma = 128
  Fine-grained Image Retrieval: m = 0.4, gamma = 80
  
  By default, we set m = 0.4 and gamma = 80
code: def get_default_reducer(self):
      return AvgNonZeroReducer()
  
file_path: pytorch-metric-learning/src/pytorch_metric_learning/losses/circle_loss.py
imports: import torch
  from ..distances import CosineSimilarity
  from ..reducers import AvgNonZeroReducer
  from ..utils import common_functions
  from ..utils import loss_and_miner_utils
  from .generic_pair_loss import GenericPairLoss
label_desc: Use image node_id 3 for calling the CircleLoss obj's underlying member method code with example usage: obj.get_default_reducer() and returns: AvgNonZeroReducer