How much would you charge for training an employee for a client?

For background, I’ve worked as an accountant for years at various accounting firms, including some of the top accounting firms in the world. I’ve always been interested in branching out on my own, but this is new to me. I have a former client who just hired an in house accountant, and they asked me to help them with training the person, since I used to do all of their accounting. They’ve estimated that they would need me for ~10 hours a week for around one month to train the person. I’m new to freelance bookkeeping, so I’m really trying to figure out how much I should charge for something like this. Hourly, flat rate, etc.

I know a lot of people are going to say it depends on your area and so on. But I’m looking for any advice I can get. How much would/do YOU charge for something like this?