@staticmethod
def producer_end(device, cfg):
    """ 
        function after finishing all of its task and before close the process.
        
        Args:
            device (str): device for this process.
            cfg (easycore.common.config.CfgNode): config of this process, you can use it to get data
                from `producer_init` and `producer_work` function.
        """
    pass
