Python 3.9.1

Python is a remarkably powerful dynamic programming language that is used in a wide variety of application domains. The language itself is a flexible powerhouse that can handle practically any problem domain. Build your own web server in three lines of code. Build flexible data-driven code using Python's powerful and dynamic introspection capabilities and advanced language features such as meta-classes, duck typing and decorators.

Python lets you write the code you need, quickly. And, thanks to a highly optimized byte compiler and support libraries, Python code runs more than fast enough for most applications.

Features of Python:

- Very clear, readable syntax.
- Strong introspection capabilities.
- Intuitive object orientation.
- Natural expression of procedural code.
- Full modularity, supporting hierarchical packages.
- Exception-based error handling.
- Very high level dynamic data types.
- Extensive standard libraries and third party modules for virtually every task.
- Extensions and modules easily written in C, C++ (or Java for Jython, or .NET languages for IronPython).
- Embeddable within applications as a scripting interface.

Changes in recent version

bpo-41815: Fix SQLite3 segfault when backing up closed database. Patch contributed by Peter David McCormick.
bpo-41662: No longer override exceptions raised in __len__() of a sequence of parameters in sqlite3 with ProgrammingError.
bpo-41662: Fixed crash when mutate list of parameters during iteration in sqlite3.
bpo-39728: fix default _missing_ so a duplicate ValueError is not set as the __context__ of the original ValueError.
bpo-41602: Add tests for SIGINT handling in the runpy module.
bpo-38249: Update Py_UNREACHABLE to use __builtin_unreachable() if only the compiler is able to use it. Patch by Dong-hee Na.