How to use the checklist.APIRegressionValidator function in checklist

Attempts to find things that are wrong with the repo -- these are usually
    annoying details introduced by human error. The code goes out of its way
    to nitpick as much as possible in order to maximize the effectiveness of
    the power trip.

    Returns
    -------
    int
        Return code: 0 if there were no validation errors, 1 otherwise. Useful
        as an exit code (e.g. for use with ``sys.exit``).

    """
    root = 'skbio'
    validators = [InitValidator(), CopyrightHeadersValidator(),
                  ExecPermissionValidator(), GeneratedCythonValidator(),
                  APIRegressionValidator()]

    return_code = 0
    for validator in validators:
        success, msg = validator.validate(root)

        if not success:
            return_code = 1
            sys.stderr.write('\n'.join(msg))
            sys.stderr.write('\n\n')

    return return_code