With the recent popularity of new programming languages that are improving the Python ecosystem, one cannot dismiss the role of "old" languages like C++, and how the new versions might stay relevant. With these ideas in mind, how do you bring a huge project, as old as Python, written in C++ to Python? If you are thinking: «...just create some bindings and call it a day» you will be surprised. On this talk, we will dive directly into the internals on how the Qt for Python project brought one of the most popular C++ frameworks into Python - but not only with 1-to1 bindings. We will discuss about build systems, packaging, limited API, interpreters support, Platform and API compatibility, Python and C++ types, ecosystem awareness, CPython code generation, communities, documentation, and many more challenging aspects of maintaining and developing a C++ library in Python. After this talk, you will not only understand why exposing an existing library from one language to another is much more than just binding them together, but also you will be able to start developing Python applications with Qt.