code: def forward(self, pprev, prev):
      return self.reduce0(pprev), self.reduce1(prev)
  
imports: import torch
  import torch.nn
  import torch.nn.functional
  from nni.nas.pytorch import mutables
  from ops import FactorizedReduce, StdConv, SepConvBN, Pool
label_desc: Use image node_id 2 for calling the ReductionLayer obj's underlying member method code with example usage: obj.forward(pprev, prev) and returns: self,  self