The predicates module provides a variety of predicates, predicate factories, and predicate partials.

“A predicate is a function that returns the truth value of some condition.”

—Andrew M. Kuchling, Python Functional Programming HOWTO

Predicate factories are functions which create new predicates based on their arguments (e.g., _and(), _nargs()). Predicate partials are functions created by partial application of a predicate’s arguments.