code: def freeze_bn(self):
      for m in self.xception_features.modules():
          if isinstance(m, nn.BatchNorm2d):
              m.eval()
  
imports: import math
  import torch
  import torch.nn
  import torch.nn.functional
  from collections import OrderedDict
  import torch.utils.model_zoo
  from torch.nn.parameter import Parameter
label_desc: Use image node_id 3 for calling the DeepLabv3_plus obj's underlying member method code with example usage: obj.freeze_bn() without return types