structured_points2d.py example file fails to write data

Hi,

I've just installed a fresh version of Mayavi from git sources, and as I want to try to write a few XML files, I have tested the example "structured_points2d.py" and uncommented the 2 lines enabling writing.

But when I run the python script, I get this error message:

traits.trait_errors.TraitError: The 'input' trait of a XMLImageDataWriter instance is 'read only'.

What's wrong?

Thanks in advance.

PS : Mayavi 4.7.2, Python 3.7.3, VTK 8.2.0