code: def forward(ctx, X, lambda_val, pad_val):
      ctx.lambda_val = lambda_val
      ctx.input_shape = X.size()
  
      Y = _C.swap_align2nat_forward(X, lambda_val, pad_val)
      return Y
  
file_path: detectron2/projects/TensorMask/tensormask/layers/swap_align2nat.py
imports: from torch import nn
  from torch.autograd import Function
  from torch.autograd.function import once_differentiable
  from tensormask import _C
label_desc: Use image node_id 1 for calling the _SwapAlign2Nat obj's underlying member method code with example usage: obj.forward(ctx, X, lambda_val, pad_val) and returns: Y