code: def start(self):
          
          def first_run():
              self._ioloop_thread_id = get_thread_ident()
              if self.OBSERVE_UPDATES:
                  self.attach()
          self.ioloop.add_callback(first_run)
docs: Start operating the strategy.
  
          Subclasses that override start() should call the super method before
          it does anything that uses the ioloop. This will attach to the sensor
          as an observer if :attr:`OBSERVE_UPDATES` is True, and sets
          :attr:`_ioloop_thread_id` using `thread.get_ident()`.