I write performant cython all the time, as a glue language. Write your "business logic" in Python. Write your class definitions and heavyweight algorithms in

I write performant cython all the time, as a glue language. Write your "business logic" in Python. Write your class definitions and heavyweight algorithms in C++. Write your API in Cython. If you're writing your business logic and heavyweight algorithms all in cython, you're in for some misery.