The final article in a series on Python packaging explores the complexities of distributing a Python package with a C extension, emphasizing the need for additional configuration compared to pure Python packages. After introducing the concept of using a C extension to improve the performance of a Python-based merging algorithm, the article details the steps taken to integrate the C code into a Python package. This involves defining a PyMethodDef function, configuring a module with PyModuleDef, and creating an initialization function, followed by building the extension using setuptools with a setup.py file, despite the use of the Poetry tool. The process includes challenges with binary packaging due to platform-specific dependencies, which can be circumvented by opting for source builds that require a C compiler. The article also highlights the importance of a MANIFEST.in file for including necessary C source files in the package, ultimately demonstrating how to publish the package on PyPi. This technical exploration underscores the intricate work behind the seemingly simple operation of pip installation, providing valuable insights for developers aiming to package Python extensions efficiently.