/**
 * Check WordLift's configuration.
 *
 * @since 3.0.0
 *
 * @return bool True if the configuration is set otherwise false.
 */
function wl_configuration_validate()
{
    // Check that the WordLift key has been set or show a notice.
    if ('' !== wl_configuration_get_key()) {
        return;
    }
    Wordlift_Notice_Service::get_instance()->add_error(sprintf(__('application-key-not-set', 'wordlift'), 'http://join.wordlift.it'));
}