diff --git a/egs/librispeech/ASR/pruned_transducer_stateless7/scaling.py b/egs/librispeech/ASR/pruned_transducer_stateless7/scaling.py
index 143690c3b..f68051938 100644
--- a/egs/librispeech/ASR/pruned_transducer_stateless7/scaling.py
+++ b/egs/librispeech/ASR/pruned_transducer_stateless7/scaling.py
@@ -1878,7 +1878,7 @@ class MulForDropout3(torch.autograd.Function):
     # grad and is zero-or-one.
     @staticmethod
     @custom_fwd
-    def forward(self, ctx, x,  y, alpha):
+    def forward(ctx, x,  y, alpha):
         assert not y.requires_grad
         ans = x * y * alpha
         ctx.save_for_backward(ans)
@@ -1887,7 +1887,7 @@ class MulForDropout3(torch.autograd.Function):
 
     @staticmethod
     @custom_bwd
-    def backward(self, ctx, ans_grad):
+    def backward(ctx, ans_grad):
         ans, = ctx.saved_tensors
         x_grad = ctx.alpha * ans_grad * (ans != 0)
         return x_grad, None, None