Finds the scalar by name and appropriately sets it as active

def set_active_scalar(self, name, preference='cell'):
        """Finds the scalar by name and appropriately sets it as active"""
        _, field = get_scalar(self, name, preference=preference, info=True)
        if field == POINT_DATA_FIELD:
            self.GetPointData().SetActiveScalars(name)
        elif field == CELL_DATA_FIELD:
            self.GetCellData().SetActiveScalars(name)
        else:
            raise RuntimeError('Data field ({}) not useable'.format(field))
        self._active_scalar_info = [field, name]