def METHOD_NAME(proj_dir, key) :
    """delete a settings value from the project-local settings file
    :param proj_dir:    absolute project directory
    :param key:         settings key
    """
    util.ensure_valid_project_dir(proj_dir)
    settings = load(proj_dir)
    if key in settings :
        del settings[key]
    save(proj_dir, settings)
    proj_name = util.get_project_name_from_dir(proj_dir)
    log.info("'{}' unset in project '{}'".format(key, proj_name))