A command-line tool (and Python library) to extract data from CommCareHQ into a SQL database or Excel workbook
Pythonic library for QuickCheck-style randomized testing and SmallCheck-style exhaustive testing of the same test suite.
"Either" and "Maybe" data structures
A robust and significantly extended implementation of JSONPath for Python, with a clear AST for metaprogramming.
A language for describing Python programs with concise higher-order annotations like "(a -> a) -> [a] -> [a]" but don't you dare call them "types"
A type language for Python, including parsing, pretty-printing, type inference, type checking, and run-time contract enforcement.