replay policy and manual policy

[qibinaoe]

HELLO! I found there are

class UtgReplayPolicy(InputPolicy):

class ManualPolicy(UtgBasedInputPolicy):

in input_policy.py , I think it has not been finished.
So is the manual policy is going to generate the UTG when the user himself generate the events?
and what's the meaning of utg repaly policy?
Thanks!