Also, it seems that ypur solution has 2 lines

You are not required to explicitly define the function. Consider how the test will invoke your function. If only there were a Greek method for assiging a function to a word....

There is a way to import stuff with less code, and there are ways to solve this kata without imports.

Calcuating the sum every time is redundant. Try to think of a way to optimize that part :>

There's a thing in Python named after a Greek letter :)

There's a type of function that has implicit 'return'.

Some cases I've gotten into went deep into 10000s of days. Take that into account.

Thanks!

Check your second if condition, it's wrong.

Don't use global vars, they keep their values between tests.