code: def test_transducer_loss_fp16_backward_fusion(self):
      loss_tst, grad_tst = self.run_transducer_loss(
          scalar_t=torch.float16,
          fuse_softmax_backward=True,
          packed_input=False,
          for_vector_kernel=False,
      )
      torch.testing.assert_close(
          self.loss_ref, loss_tst, atol=1e-5, rtol=1e-5
      )
      torch.testing.assert_close(
          self.grad_ref, grad_tst, atol=1e-4, rtol=1e-3
      )
  
file_path: apex/apex/contrib/test/transducer/test_transducer_loss.py
imports: import unittest
  import torch
label_desc: Use image node_id 8 for calling the TransducerLossTest obj's underlying member method code with example usage: obj.test_transducer_loss_fp16_backward_fusion() without return types