code: def forward(self, x):
      raise NotImplementedError(
          "Base gate cannot be directly used for fwd"
      )
  
file_path: fastmoe/fmoe/gates/base_gate.py
imports: import torch.nn
label_desc: Use image node_id 2 for calling the BaseGate obj's underlying member method code with example usage: obj.forward(x) without return types