'Retry handler.
This is run by the worker when the task is to be retried.
Arguments:
exc (Exception): The exception sent to :meth:`retry`.
task_id (str): Unique id of the retried task.
args (Tuple): Original arguments for the retried task.
kwargs (Dict): Original keyword arguments for the retried task.
einfo (~billiard.einfo.ExceptionInfo): Exception information.
Returns:
None: The return value of this handler is ignored.'

def on_retry(self, exc, task_id, args, kwargs, einfo):

    pass
