Clair de Lune

I sat down and worked out the scale of Clair de Lune, and revised my earlier opinion. I am now sure it's in the key of D flat major. I'll have my opinion verified by Teacher in a day or so but I'm pretty sure. This is the key signature of D flat Major:
Which by golly is the bulk of Clair de Lune. But I figured it out by myself using the Tetrachord rule. Every scale consists of two Tetrachords connected by a whole step. If you know this, you can figure out the fingering or pattern of every key. I looked at the lowest flat, in this case "d" and started playing the scale there. It just so happened this played a perfect Major Scale. If it hadn't, I would have tried another flat note. I knew the scale was neither 'C" nor "F" Major; neither would have that particular pattern of flats. In fact C Major has no flats.

It's cool knowing enough Music Theory to understand this much at least. I dig it.