I agree. The question suggests that the strng is a bunch of letters followed by numbers, not !@$#%$@%53632gs#@$@%$#32g436. I tailored my solution to solved the first not second kind of test case. If I want to get this kata marked as solved, I am going to have to start from scratch (which I won't)!

Really frustrating. I thought that initially as well and tailored my solution to it. When it was only letters and numbers, it passed. But with the random test cases I got a bunch of bugs, and now i have to write the code all over again( which I won't). all the different test cases should have been specified in the problem description . This is necessary because any one who tries to solve a problem needs to understand what test cases exist to write a solution around them.

The creator of this kata probably did this to avoid name conflicts. 'str' might be interpreted by python as the built in function. 'string' might cause some issues as well.