> Lambdas are for "one-liners", functions are for more-liners.

The problem, though, is that this is entirely a Python conceit. It is in no way, shape, or form any kind of programming truism. In fact, taking a more principles-oriented approach, a named function is really just a special case of a lambda. I think this may be one of those things that using a LISP (such as Scheme or Common Lisp) helps people realize.

This:

    (define (foo n)
      ( . . . ))

. . . is just syntax sugar for this:

    (define foo
      (lambda (n)
        ( . . . )))

The fact that the syntax sugar is all many languages expose to the programmer doesn't change that fact, and the one-line restriction on "lambdas" in Python seems quite arbitrary.