Mark triangles as RequiredTriangles in vtk file using python


I am trying to remesh vtk files while keeping periodicity. I have had success in doing so with .mesh files by marking triangles as RequiredTriangles “by hand” (ie: by counting the correct triangles and enumerating their ID tag, then writing them in another .mesh file along with the original mesh data)
However, in order to avoid errors, I wish to stop converting my meshes from .vtk to .mesh

My problem is that I cannot find a way to mark triangles in a vtk mesh as RequiredTriangles. I am using Python for my project.

Thanks in advance for any help or advice