It's unspecified if the return array needs to be allocated.

doesnt follow PEP-8

• The use of bitwise operations is not enforced
• The function name should be in snake_case
• 5000 tests is too much
• There're already several katas like these: both limited and not limited to bitwise operations only

Log
Input: a a a  b  c c  d d d d  e e e e e
Expected that e is the most common word.
Expected that d is the second most common word.
Expected that e is the third most common word.

How is that possible?

this only serves as a translation of that kata in primitive C programming language

So it's a duplicate, isn't it?