The generateVTUFromDiag function of generateVTUFromDiag.py takes an array representing a persistence diagram (like [[0, 10], [4, 5], [6, 8]] and create a vtkUnstructuredGrid representing the diagram.
It is the necessary format for algorithms of TTK.
The generateAndSaveDiags function takes an array of persistence diagrams (like represented before) and saves a Multi-Block DataSet in a .vtm format, consisting of many vtkUnstructuredGrid representing the diagrams.