Since my mother is visiting me in Buenos Aires this week, I went around the neighborhood to get an extra set of door keys made. However, every locksmith I visited gave me a blank look after they saw one of the keys I wanted to reproduce.
"What's this?" locksmith X, Y, and Z all asked.
"My door key," I would reply.
All told me they don't have the key I wanted and probably nobody in Buenos Aires does.
Finally, the fourth locksmith I visited told me I have a yankee key, that he doesn't have it either, and asked me why I'm doing with such a key.