I can use Tullio to define a matrix multiplication function `matmul(A, B)`

as such:

```
using Tullio
matmul(A, B) = @tullio C[i, k] := A[i, j] * B[j, k]
```

I’d like to also define a function `matmul!(C, A, B)`

that stores the result by overwriting `C`

instead of creating a new matrix.

Is this possible with Tullio?