Demo fetches the first problem in each language track.

Fetch retrieves problems from the API.

Submit posts code to the API.

Tracks gets the current list of active and inactive language tracks.

Unsubmit deletes a submission.

UserAgent lets the API know where the call is being made from.

Iteration represents a version of a particular exercise.

PayloadError represents an error message from the API.

PayloadProblems represents a response containing problems.

PayloadSubmission represents metadata about a successful submission.

Problem represents a specific problem in a given language track.

Submission is an iteration that has been submitted to the API.

Track is a collection of problems in a given language.