Python Script: How to locally refine the mesh for lines?

Hello,

In my python script I would like to locally refine the mesh for some lines. 

I had a look in the Plaxis command index via the Scripting reference and from what I understand there is only a python command for global refinement.

So is there any existing command line?

I was trying the following commands:

            for line in g_i.lines:

                               mesh = 0.5

                               g_i.set(line.coarsenessfactor,(mesh))

But it says that requested attribute coarsenessfactor is not present…

Any idea,

Thank you, 

Pascal