question: How to not create lightning_logs when using a external logger like wandb ?
context: I would like my wandb logger to just place their data under wandb dir, and checkpointcallback to save ckpts under dir_path I specified.
  And I don't want pl to create lightning_logs and files under it, but I can't set logger=False b/c I use a logger. Is there any suggestion ?
answer: You can set the save_dir in WandbLogger, something like
  logger = WandbLogger(save_dir="wandb", ...)
  Trainer(logger=logger, ...)
  This should work (haven't tested it).
  Then your logs and checkpoints will save to two different locations.