@ahojnnes Since we only want the for loop to be outsourced, I am still confused about how the two files `.py` and `.pyx` will manage the program flow among themselves once the function `brief` is called. My doubts about Cython here are pretty low-level like - Would I need to write the whole program in Cython? If I just need to implement the for loop in Cython, how would that be imported and called from `.py` file. I looked at this tutorial(https://python.g-node.org/python-summerschool-2011/_media/materials/cython/cython-slides.pdf) but it discussed about writing complete Cython programs, unlike the case here. Any pointers/examples in the codebase would be appreciated. Till then I will push the amendments since the last commit.