I&#x27;m not a Python developer but what I&#x27;ve seen and find frustrating is the slow migration of libraries to Python 3.  Some projects have switched to 3 and some are sticking with 2 for now.  Some applications are using 2 because they have dependencies using 2, but as those dependencies switch applications have to deal with combining Python 2 and Python 3 dependencies.<p>I know each issue is easy in isolation, but we&#x27;re talking about old 25M line codebases here.  If such things exist in Python it can be a maintenance problem.<p>I&#x27;m in favor of languages making breaking changes occasionally but there is something to be said for languages like Java or Fortran that are intended to keep compatibility forever.