The challenge:

Write a function that returns a list of n functions, such that each one, when called, will return the input value, incremented by an increasing number.

You should use a for loop, lambda, and a keyword argument

Not clear? here's what you should get:

    In [96]: the_list = function_builder(4)
### so the_list should contain n functions (callables)

    In [97]: the_list[0](2)
    Out[97]: 2
## the zeroth element of the list is a function that add 0
## to the input, hence called with 2, returns 2

    In [98]: the_list[1](2)
    Out[98]: 3
    ## the 1st element of the list is a function that adds 1
    ## to the input value, thus called with 2, returns 3

    In [100]: for f in the_list:
        print f(5)
       .....:
    5
    6
    7
    8
### If you loop through them all, and call them, each one adds one more to the input, 5... i.e. the nth function in the list adds n to the input.

Extra credit:

Do it with a list comprhension, instead of a for loop

TDD:

In lambda_keyword.py, there is a function defined:

def function_builder(n):
    ## put something in here...
    pass

Clearly, it does nothing. However in test_lambda_keyword.py there are some tests -- you can run them, but they will fail::

$ py.test test_lambda_keyword.py ... ... > assert func_list[0](12) == 12 E TypeError: 'NoneType' object has no attribute '__getitem__'

test_lambda_keyword.py:42: TypeError =========================== 3 failed in 0.04 seconds ===============

Your goal is to fill in that funciton so that those tests pass.

"Cheating"

Note that those tests only test a few things, and with small values -- so you could pretty easily hard-code a bunch of stuff to make them pass -- but what's the fun of that?

This is eveidence that "full test coverage" is a fantasy!