# Parallel Letter Frequency Count the frequency of letters in texts using parallel computation. Parallelism is about doing things in parallel that can also be done sequentially. A common example is counting the frequency of letters. Create a function that returns the total frequency of each letter in a list of texts and that employs parallelism. ## 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 shold write: ```python raise Exception("Meaningful message indicating the source of the error") ``` ## Submitting Exercises Note that, when trying to submit an exercise, make sure the solution is in the `$EXERCISM_WORKSPACE/python/parallel-letter-frequency` 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). ## Submitting Incomplete Solutions It's possible to submit an incomplete solution so you can see how others have completed the exercise.