code: def freeze_bn(self):
      for m in self.modules():
          if isinstance(m, nn.BatchNorm2d):
              m.eval()
  
file_path: pywick/pywick/models/segmentation/testnets/deeplabv2.py
imports: from collections import OrderedDict
  import torch
  import torch.nn
  import torch.nn.functional
  from .resnet import _ConvBatchNormReLU, _ResBlock
  from .msc import MSC
label_desc: Use image node_id 3 for calling the DeepLabV2 obj's underlying member method code with example usage: obj.freeze_bn() without return types