I’m trying to calculate the inverse transformation of a BSpline Transformation and I’m following the instructions of this link here in the Discourse. Here is the code I’m using:

```
#Calculating the inverse of the Bspline
disp_field_bs = sitk.DisplacementFieldTransform(BS_result)
BS_inverse = disp_field_bs.GetInverseDisplacementField()
```

The problem is that I’m getting some error:

`sitk::ERROR: Transform is not of type DisplacementFieldTransform!`

I’ve checked the documentation and the DisplacementFieldTransform class has a constructor which accepts a Transformation. So what is the problem here?