code: def next_state(self):
          
          if(self.roaster.get_roaster_state() == 'roasting'):
              self.roaster.time_remaining = 20
              self.roaster.cool()
          elif(self.roaster.get_roaster_state() == 'cooling'):
              self.roaster.idle()
docs: This is a method that will be called when the time remaining ends.
          The current state can be: roasting, cooling, idle, sleeping, connecting,
          or unkown.