# Proverb For want of a horseshoe nail, a kingdom was lost, or so the saying goes. Given a list of inputs, generate the relevant proverb. For example, given the list `["nail", "shoe", "horse", "rider", "message", "battle", "kingdom"]`, you will output the full text of this proverbial rhyme: ```text For want of a nail the shoe was lost. For want of a shoe the horse was lost. For want of a horse the rider was lost. For want of a rider the message was lost. For want of a message the battle was lost. For want of a battle the kingdom was lost. And all for the want of a nail. ``` Note that the list of inputs may vary; your solution should be able to handle lists of arbitrary length and content. No line of the output text should be a static, unchanging string; all should vary according to the input given. ## Exception messages Sometimes it is necessary to raise an exception. When you do this, you should include a meaningful error message to indicate what the source of the error is. This makes your code more readable and helps significantly with debugging. Not every exercise will require you to raise an exception, but for those that do, the tests will only pass if you include a message. To raise a message with an exception, just write it as an argument to the exception type. For example, instead of `raise Exception`, you should write: ```python raise Exception("Meaningful message indicating the source of the error") ``` ## Running the tests To run the tests, run the appropriate command below ([why they are different](https://github.com/pytest-dev/pytest/issues/1629#issue-161422224)): - Python 2.7: `py.test proverb_test.py` - Python 3.4+: `pytest proverb_test.py` Alternatively, you can tell Python to run the pytest module (allowing the same command to be used regardless of Python version): `python -m pytest proverb_test.py` ### Common `pytest` options - `-v` : enable verbose output - `-x` : stop running tests on first failure - `--ff` : run failures from previous test before running other test cases For other options, see `python -m pytest -h` ## Submitting Exercises Note that, when trying to submit an exercise, make sure the solution is in the `$EXERCISM_WORKSPACE/python/proverb` directory. You can find your Exercism workspace by running `exercism debug` and looking for the line that starts with `Workspace`. For more detailed information about running tests, code style and linting, please see the [help page](http://exercism.io/languages/python). ## Source Wikipedia [http://en.wikipedia.org/wiki/For_Want_of_a_Nail](http://en.wikipedia.org/wiki/For_Want_of_a_Nail) ## Submitting Incomplete Solutions It's possible to submit an incomplete solution so you can see how others have completed the exercise.