import statements not needed

[agporto]

SlicerExtension-VMTK/ExtractCenterline/ExtractCenterline.py

Line 442 in 2b17b3d

def preprocess(self, surfacePolyData, targetNumberOfPoints, decimationAggressiveness, subdivide):

It seems like the referenced import statements are not necessary (left-over from previous implementations?)

[lassoan]

We'll review this issue after VMTK build system is updated for VTK9.