is fuctional better performing? I assumr it's at least more readable.

not a kata suggestion

11 tests passing and 20 tests failing with the below error. Tried changing the column orders just to see if that is the issue, which is not. I am not touching the objects in the given DFs. So unable to figure it out.
Give me some guidance.

Column types are different:

P float64
B float64
A float64
dtype: object

Should be

B float64
A float64
P float64
dtype: object

Can I borrow your brain harddisk for sometime... Nice one

Lesson learnt... We have to understand what we are trying to check, and then use the correct functions...

Algorithm needs to be re-thought in functional paradigm. This solution procedural.
Give functional a try....

The logic in the check() method seems to be wrong. Re-think with following questions

1. What conditions needs to be checked by the User class before executing the check() method?
2. How to implement those conditions?
3. Which of these conditions needs to raise exceptions?

Follow the DRY (Don't Repeat Yourself) principle.That is why OOP was created.

4. What made you to repeat the add_cash and withdraw methods? Check your understanding
   All the very best.

Clever implementation...

Beginners struggling to wrap around OOPS concept will find this Kata very satisfactory

Yeah, you were right. I checked.