It is best if you are able to padlock your bike away, so whether the shed has a place for a padlock to slide into or the cover can be locked by a padlock or a TSA lock. I personally prefer a TSA lock as it feels a bit more secure than a simple padlock and padlocks can run the risk of losing the key whereas a TSA lock is a code that needs to be in the right order for the lock to be undone.