code: def action_delete(self, courseid, taskid, path):
          
          # normalize
          path = path.strip()
          if not path.startswith("/"):
              path = "/" + path
  
          wanted_path = self.verify_path(courseid, taskid, path)
          if wanted_path is None:
              return self.show_tab_file(courseid, taskid, _("Internal error"))
  
          # special case: cannot delete current directory of the task
          if "/" == wanted_path:
              return self.show_tab_file(courseid, taskid, _("Internal error"))
  
          try:
              self.task_factory.get_task_fs(courseid, taskid).delete(wanted_path)
              return self.show_tab_file(courseid, taskid)
          except:
              return self.show_tab_file(courseid, taskid, _("An error occurred while deleting the files"))
docs: Delete a file or a directory