+wait_for=str Specifies the name of the already defined job to wait
+ for. Single waitee name only may be specified. If set, the job
+ won't be started until all workers of the waitee job are done.
+
+ Wait_for operates on the job name basis, so there are a few
+ limitations. First, the waitee must be defined prior to the
+ waiter job (meaning no forward references). Second, if a job
+ is being referenced as a waitee, it must have a unique name
+ (no duplicate waitees).
+