class_docstr: Fused operation which performs following three operations in sequence
  
      1.  Scale the tensor.
      2.  Apply the mask.
      3.  Perform softmax.
code: def backward(ctx, output_grads):
      softmax_results, scale_t = ctx.saved_tensors
  
      input_grads = scaled_masked_softmax.backward(
          output_grads, softmax_results, scale_t[0]
      )
      return input_grads, None, None, None
  
imports: import enum
  import torch
  import torch.nn
  from colossalai.kernel.op_builder.scaled_masked_softmax import ScaledMaskedSoftmaxBuilder
  from colossalai.kernel.op_builder.scaled_upper_triangle_masked_softmax import ScaledUpperTrainglemaskedSoftmaxBuilder
label_desc: Use image node_id 2 for calling the ScaledMaskedSoftmax obj's underlying member method code with example usage: obj.backward(ctx, output_grads) and returns: input_grads,  None,  None,  None