class_docstr: Base class for transition.
  
  Args:
      in_channels (int): Number of input channels.
      out_channels (int): Number of output channels.
code: def forward(x):
      pass
  
imports: import torch.nn
  import torch.nn.functional
  from mmcv.cnn import ConvModule
  from mmengine.model import BaseModule
  from mmdet.registry import MODELS
label_desc: Use image node_id 2 for calling the Transition obj's underlying member method code with example usage: obj.forward(x) without return types