code: def backward(ctx, grad_output):
      input = ctx.saved_tensors
      grad_input = grad_output
      grad_input[input[0].gt(1)] = 0
      grad_input[input[0].lt(-1)] = 0
      return grad_input
  
imports: import dgl
  import torch
  import torch.nn
  import torch.nn.functional
  from torch.autograd import Function
  from torch.nn import Parameter
  from torch.nn.modules.utils import _single
label_desc: Use image node_id 2 for calling the BinaryQuantize obj's underlying member method code with example usage: obj.backward(ctx, grad_output) and returns: grad_input