What exactly does resolveConflictingSavedGames in GameKit do?

According to the documentation, The GameKit function resolveConflictingSavedGames resolves conflicting saved games. However, I don't really understand what it does exactly, and how to use it.

• Does it replace the data in all saved games in the provided conflictingSavedGames array with the data provided in Data?
• Do I have to handle the GKSavedGame passed to the completion handle in some way? I.e manually erase the old ones and save the new savedgame?
• Am I supposed to call it when loading or saving?
• Should I always call it when there are multiple savedgames tied to one filename?

The function:

 func resolveConflictingSavedGames(
      _ conflictingSavedGames: [GKSavedGame],   
      with data: Data, 
      completionHandler handler: (([GKSavedGame]?, Error?) -> Void)? = nil)

Documentation for resolveConflictingSavedGames