code: def forward(ctx, input):
      ctx.save_for_backward(input)
      out = torch.sign(input)
      return out
  
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 1 for calling the BinaryQuantize obj's underlying member method code with example usage: obj.forward(ctx, input) and returns: out