User prefix, code not working in discord.py rewrite branch

guys! I'm pretty new to dpy btw How do you make a user prefix? For example Asios prefix is ! Which is the default prefix , but i want to give Bsio a different prefix. I'm stuck on how to get the prefix, i couldn't find any tutorial or in the docs.

def pr(ctx, message): if message.author == 0000000: prefix = "!" else: prefix = "_" It just doens't work.