I am adding a native function and having trouble using other utility methods w/in ATen.  For example, see this simple native function 8
This is the quick test I’m using:
import torch

s = torch.sparse.DoubleTensor(
                torch.LongTensor([[0,2,0], [0,2,1]]),
                torch.FloatTensor([[1,2],[3,4],[5,6]]),
                torch.Size([3,3,2]))

s.my_op()

Calling self._sparseDims() on line 153 works just fine as expected.  This function is part of the public API and is dispatched to _sparseDims_sparse here 1, which calls _get_sparse_impl.  And _get_sparse_impl is defined in this header, which is included in the file I’m defining my function in.
So the question is this:  what magic am I missing to be able to use the same helper function in the same way in my native op?