docstr: Update sampled class to memory bank, make the class center stored
  in the memory bank the latest.
  
  Parameters
  ----------
  index: NDArray
      Local index for memory bank to sample, start from 0 to num_local.
  updated_weight: NDArray
      Class center which has been applied gradients.
  updated_weight_mom: NDArray
      Class center momentum which has been moved average.
code: def set(self, index, updated_weight, updated_weight_mom=None):
      """
      Update sampled class to memory bank, make the class center stored
      in the memory bank the latest.
  
      Parameters
      ----------
      index: NDArray
          Local index for memory bank to sample, start from 0 to num_local.
      updated_weight: NDArray
          Class center which has been applied gradients.
      updated_weight_mom: NDArray
          Class center momentum which has been moved average.
      """
  
      self.weight[index] = updated_weight
      self.weight_mom[index] = updated_weight_mom
  
file_path: insightface/recognition/partial_fc/mxnet/memory_bank.py
imports: import os
  import numpy
  from mxnet import nd
  import mxnet
  from memory_samplers import WeightIndexSampler
label_desc: Use image node_id 4 for calling the MemoryBank obj's underlying member method code with example usage: obj.set(index, updated_weight, updated_weight_mom) without return types