Lambdas and the lambda calculus
In a book on a purely functional programming language, it would be necessary to explain lambda calculus, and the technique invented by Haskell Curry that we call
currying. Python, however, doesn't stick closely to this kind of lambda calculus. Functions are not curried to reduce them to single-argument lambda forms.
We can, using the functools.partial function, implement currying. We'll save this for Chapter 10, The Functools Module.