Python has been called "built-in battery" programming language, which has been used as a propaganda advantage in Python. But after years of development, Python built a lot of "battery" has been well spent, or because of changes in the external tool or platform has led to no useful here. The presence of these "used batteries", not only increases the maintenance Python standard library when each upgrade version of the workload, and will mislead the novice to use some not so good ways. No matter how you look, "used batteries" are discarded more cost-effective.
So, Christian Heimes proposed PEP 594, it is recommended to remove these old dilapidated or poorly designed standard library. The removal process is still relatively modest, it may be just the beginning of the document is not recommended, and then give some warning when using slowly, and finally we all know is really going after the removal of the module prepared for removal. Most of the work will be removed at the completion of 3.10 Python. The current stable version is Python 3.7, Python3.8 still in development, but also 3.10 released almost three years.
So what is the standard library in the list to prepare to remove it? Below is a list of recommended PEP 594 is given. The next time you write code, if used in the list of libraries, we must consider is not a substitute for the need to choose.