Key for gas connection box

The workmen had left the gas connection box to my house open. So I looked for a key, but as I couldn't find one, I ended up creating one myself on fusion 360.
I live in Belgium and don't know whether this key is universal or used elsewhere in the world.
It looks like a triangle with the points broken off. In the end, it's a hexagonal shape with 3 long sides and 3 short ones in between.