flake8 fix

torchsparsegradutils/indexed_matmul.py

@@ -42,7 +42,6 @@ def segment_mm(a, b, seglen_a):
     if not a.shape[1] == D1 or not seglen_a.shape[0] == R:
         raise ValueError("Incompatible size for inputs")
 
-    torchdevice = a.device
     segidx_a = torch.cumsum(seglen_a[:-1], dim=0)
 
     # Ideally the conversions below to nested tensor would be handled natively