Extracting Data from CFF Fluent Files to CSV File

for quick sanity checks of simulation results from Fluent I would like to generate an Image of the 3d data cut a long a predefined plane. Since the vtkFLUENTCFFReader is very new I did only find the test cases given in the gitlab repository ( TestFLUENTCFFReader_3D.py and TestFLUENTCFFReader.py) . However, since they rely on the rendering capabilities of VTK, it is required to have a X-Server running on the machine. As this is not always the case for HPC-clusters, my desired approach would be to extract the data and store it in a numpy-array or CSV-File for the last time step. Generally, I would like to use the approach given in another discourse discussion. What is the proper way to extract the data from the vtkMultiBlockDataSet given as output of the Reader?
Any suggestions are very appreciated.

I actually found a solution for my problem by myself. One can extract blocks from a vtkMultiBlockDataSet using the GetBlock() function. The modifying and plotting is inspired by the gist of mrklein. My complete code can be found in a git by me.