fix MapDataset creation in python 3.9
Summary:
fix
The old code works for python 3.6 & 3.7; fails for python 3.9
@@ -74,7 +74,7 @@ class MapDataset(data.Dataset):
if is_iterable:
return _MapIterableDataset(dataset, map_func)
else:
- return super().__new__(cls, dataset, map_func)
+ return super().__new__(cls)
def __getnewargs__(self):
return self._dataset, self._map_func
