code: def backward(ctx, grad_output: Tensor) -> Tensor:  # type: ignore[override]
      mask = ctx.saved_tensors
      return grad_output * mask
  
imports: import torch
  from torch import Tensor
  from torch.ao.quantization.experimental.quantizer import quantize_APoT, dequantize_APoT
label_desc: Use image node_id 2 for calling the fake_quantize_function obj's underlying member method code with example usage: obj.backward(ctx, grad_output) and returns: unknown