Where can i make magical potions at?

I was walking down the street Detroit Michigan (home of the peace dude Ghandi) yesterday i think it was at approximately 3:27 and saw a sign that read "Magical potion making classes here today from 10 am to 4 pm" and i thought to myself that would be a wonderful thing to take up my spare time since all i do is sit around and get paid by the government because basically im waaaay tooo lazy to work. Well i also pee off of my roof all day long but after 7 years of this im starting to get a tad bored of it. So anyway i saw this sign while i was cruising the streets i think it was and see i just dont remember where i saw it because i have this "disease" that i sometimes will wander the streets mindlessly for days and not remember where i am and dont get home till a ship apears in the sky and "transports" me back to my house. But what i was wondering is if there are any people who were at that meeting and if they had snacks, oh and if you were at that meeting where is it? do you think that you could provide me with simple and concise directions to the location of the place where you can make magical potions at. It would be really nice if you could also provide a map to get me there safety.