code: def forward(self, input_):
      return input_.mean(self.dim, self.keep_dim)
  
imports: import torch
  import torch.nn
  import torch.nn.functional
  from pywick.models.segmentation.da_basenets.segbase import SegBaseModel
  from pywick.models.segmentation.da_basenets.fcn import _FCNHead
label_desc: Use image node_id 2 for calling the Mean obj's underlying member method code with example usage: obj.forward(input_) and returns: input_