how to write script for filtering by classes ?

[tournevase]

hello
an agisoft project includes 7 chunks
for each chunk i defined 3 classes in the dense clouds (same names for all the chunks)
i need to filter the chunks by the 3 classes, but it is hard to do this by the menu worktools
so i want to do this in one shot by a script
in the Metashape Python Reference i found something :
"setClassesFilter(point_classes)
Set filter by point classes.
Parameters point_classes (PointClass or list of PointClass) – List of point classes "
how the script could be writen ?
thank's 
 

[Alexey Pasumansky]

Hello tournevase,

What result you are expecting from such filtering? Leave only three classes that you have assigned (what are their names?) in every chunk and remove the points from other classes?