On my last day in Kiev, I left my bags, with my passport and keys, in the left luggage lockers in the main train station. You had to set a code which was letters instead of numbers, using three dials. I thought I had done it correctly, but when I came back couldn’t get the thing open.
I went to the women running the place and tried to explain my predicament to them, one of them reluctantly came with me and then started shouting a question at me I couldn’t understand.
I guessed that she was asking if I could identify what is in the locker. I typed in what my bags were like, got a translation into Russian and was able to play that to her, which seemed to satisfy her to the extent of opening the locker.
It really saved my bacon. Do not go to Ukraine without a local sim and a translation app.