How can I use SaveData to write an ASCII file in ParaView 3.98.1?

ParaView Support
11

I found out I can also do the following to save my file as ASCII in this version:

write = servermanager.writers.DataSetWriter()
write.Input = vtk_file
write.FileName = filename
write.FileType = 'Ascii'
write.UpdatePipeline()

I do not know, however, how to link a proxy (see SaveData's call) using this approach since the class does not have a Proxy attribute.