code: def on_open(self, callback, period):
          
          super().on_open()
          self.callback = callback
          self.period = period
          self.reset_event = asyncio.Event(loop=self.loop)
docs: Initialize a new timer.
  
          :param callback: The function or coroutine function to call on each
              tick.
          :param period: The interval of time between two ticks.