QuantWrapper
class torch.quantization.QuantWrapper(module)
A wrapper class that wraps the input module, adds QuantStub and
   DeQuantStub and surround the call to module with call to quant and
   dequant modules.
This is used by the quantization utility functions to add the
   quant and dequant modules, before convert function QuantStub
   will just be observer, it observes the input tensor, after
   convert, QuantStub will be swapped to nnq.Quantize which does
   actual quantization. Similarly for DeQuantStub.