Living it safe

Our apartment block entrance door looks like a door to a safe, in fact all apartment block doors that I have seen here are very safe-looking. They are also always open. But when I came home the other day the door was closed! I tried to pull it open - it didn't move. I looked at my two keys, but there was no key hole to put any of them in (I hadn't noticed the absence of a key hole before). I felt slightly desperate. There aren't that many apartments here and this was in the middle of the morning, a time when not so many people leave or come back. I thought that Odnoo was out, but I rang her and she was at home! Saved! She then told me that there actually is a code lock (the little knobs that you can perhaps see are the keys to press). If the code lock works is of course another matter.