torch.jit.unused
torch.jit.unused(fn)
This decorator indicates to the compiler that a function or method
   should be ignored and replaced with the raising of an exception.
   This allows you to leave code in your model that is not yet
   TorchScript compatible and still export your model.
  Example (using "@torch.jit.unused" on a method):

     import torch
     import torch.nn as nn

     class MyModule(nn.Module):
         def __init__(self, use_memory_efficient):
             super(MyModule, self).__init__()
             self.use_memory_efficient = use_memory_efficient

         @torch.jit.unused
         def memory_efficient(self, x):
             import pdb
             pdb.set_trace()
             return x + 10

         def forward(self, x):
             # Use not-yet-scriptable memory efficient mode
             if self.use_memory_efficient:
                 return self.memory_efficient(x)
             else:
