def mark_as_tiltseries(dataobject): from vtk import vtkTypeInt8Array fd = dataobject.GetFieldData() arr = fd.GetArray("tomviz_data_source_type") if arr is None: arr = vtkTypeInt8Array() arr.SetNumberOfComponents(1) arr.SetNumberOfTuples(1) arr.SetName("tomviz_data_source_type") fd.AddArray(arr) arr.SetTuple1(0, 1)