it seems he is working for Google and have no time to answer

very cool my boy

Thank you. Republished

With the issues addressed and closed, you can republish the kata.

Changed to margin of error.

Changed to margin of error on perceived time per JohanWiltink's comment

Rounding is not the correct way to handle floating point representation inaccuracy, testing with an error margin is. This is documented.

Round to 2 decimals.

This is not enough information. In addition to the required precision, the kata should also specify the rounding method (e.g., half-to-even), and when to apply the rounding (e.g., on the sum at the end).

I like the logic behind your solution. Very similar to mine

Good one with the prototype. but if the object will be created with the class, the prototype is created automatically.

Sure! Thanks a lot!

It works without return because the sample test (scroll a bit to see it in the coding page) tries to call factorial(). Talking about what he imported from math, factorial, it is imported as a function after all. Hope you get it.

seems this to be the faster code
I've tested with timeit module.
This Win!

Got it, thanks! The string before the method is actually the separator. Right. Thanks.