The tests (seems to be both JS and Python) test "exact" notes on frets that don't exist. For example: note=F#, exact=true, string=3, position=2 where the 3rd string only contains a single F#. It should either be mentioned in the description that these "hypothetical positions" are tested, or just removed from the test cases.

There was no error in my code in terms of math operation. Due to Python's limitations, the division of two very large integers, one a multiple of the other, was causing an error. It took me hours to get over this problem. I hope one day I can solve it much faster.

You will never receive an array with only one digit repeated n times

This means that you won't get arrays like these:

[1, 1, 1, 1]
[5, 5, 5, 5, 5, 5, 5]
[0, 0, 0]

for the input arr = ['9', '8', '8', '7', '6', '1', '0', '0', '0', '0'] I get the list [75600, 167889, 9887610000].

Looks good to me.

https://peps.python.org/pep-0238/

https://docs.python.org/3/tutorial/floatingpoint.html

Take a look at the test output. Which values differ? In which ways do they differ? Why might that be?

Also look at https://docs.python.org/3/tutorial/floatingpoint.html

What is meant by the following statement: "You will never receive an array with only one digit repeated n times."
I would be glad if an example can be given.
Also, for the input arr = ['9', '8', '8', '7', '6', '1', '0', '0', '0', '0']
I get the list [75600, 167889, 9887610000]. Do I have a mistake? Because I've spent a lot of time and I still can't see what the problem is.

you need to count the unique values