How to get a manual control definition take over any other form of control in Syskit

manual_control.rb

module Tasks
  # Make sure that no control layer but ManualControl are running
  class MaintainManualControl < Roby::Task
    terminates
    
    poll do
      control_tasks = plan.find_tasks(Services::Control).not_finished
      ready = true
      control_tasks.each do |t|
        next if t.fullfills?(Compositions::ManualControl)
        ready = false
        if !t.finishing? && t.running?
          t.stop!
        end
      end
      if ready
        ready_event.emit
      end
    end
  end
end

module Actions
  class Control < Roby::Actions::Interface
    use_profile Profiles::Control

    describe "get manual control"
    def manual_control 
      maintain = Tasks::MaintainManualControl.new
      control  = manual_control_def
      maintain.depends_on(control, role: 'control_chain')
      control.should_start_after maintain.ready_event
      maintain
    end
  end
end