def remove(action)
      raise ArgumentError.new('Expecting an action') unless action.is_a?(Action)
      @actions.delete(action)
      wakeup if running?
    end
def remove(action)
      raise ArgumentError.new('Expecting an action') unless action.is_a?(Action)
      @actions.delete(action)
      wakeup if running?
    end
action:: Action to remove from timer
 Remove given action from timer