ignore mkdir tasks when drawing flowchart

[Alfy]

I have this problem when drawing flowchart using ruffus, it includes all mkdir tasks with names like "mkdir(<function some_func at 0x7ff5613aa378>,formatter(),'{subpath[0][1]}/task_x') before taskx", the naming is very lengthy and makes the graph ugly with huge boxes for mkdir tasks. How could I ignore the mkdir tasks in the flow chart or shorten its name (e.g. to just "mkdir before task_x").

Thanks!