code: def free_memory(self):
          
          self.main.free_memory()
          QTimer.singleShot(self.INITIAL_FREE_MEMORY_TIME_TRIGGER,
                            lambda: self.main.free_memory())
          QTimer.singleShot(self.SECONDARY_FREE_MEMORY_TIME_TRIGGER,
                            lambda: self.main.free_memory())
docs: Free memory signal.