Error "A non-void function must return a value in all possible paths.'

this error is showing in this function,

static func load_savegame() -> Resource:
	if not ResourceLoader.has_cached(SAVE_GAME_PATH):
		return ResourceLoader.load(SAVE_GAME_PATH, "", true)

Should I use the resource path in the function or a different path for a saving an loading system?
Some samples could also help.

You could add:

else:
    return null

Then the caller of the function could check the function's result with is_instance_valid().