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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def curvature(self, curv_type='mean'):
 """ Returns the pointwise curvature of a mesh Parameters mesh : vtk.polydata vtk polydata mesh curvature string, optional One of the following strings Mean Gaussian Maximum Minimum Returns ------- curvature : np.ndarray Curvature values """

        curv_type = curv_type.lower()

        # Create curve filter and compute curvature
        curvefilter = vtk.vtkCurvatures()
        curvefilter.SetInputData(self)
        if curv_type == 'mean':
            curvefilter.SetCurvatureTypeToMean()
        elif curv_type == 'gaussian':
            curvefilter.SetCurvatureTypeToGaussian()
        elif curv_type == 'maximum':
            curvefilter.SetCurvatureTypeToMaximum()
        elif curv_type == 'minimum':
            curvefilter.SetCurvatureTypeToMinimum()
        else:
            raise Exception('Curv_Type must be either "Mean", ' +
                            '"Gaussian", "Maximum", or "Minimum"')
        curvefilter.Update()

        # Compute and return curvature
        curv = _get_output(curvefilter)
        return vtk_to_numpy(curv.GetPointData().GetScalars())