That argument makes no sense. Mercurial isn't part of Python, and is essentially a black box tool. We use mercurial for a C++ project at work. Does that make

That argument makes no sense. Mercurial isn't part of Python, and is essentially a black box tool. We use mercurial for a C++ project at work. Does that make it a Python and C++ project? Obviously not. You might as well argue that if Python3 were so great the devs wouldn't be using C and C++ in their toolchain, which is what most of the underlying operating system and tools are written in. And in that case, the argument would apply to almost every language and implementation out there.