check.
	 * @return boolean             True if the role can publish.
	 */
	protected function can( $capability, $role ) {
		if ( empty( $role ) ) {
			return current_user_can( $capability );
		}

		$wpRoles  = wp_roles();
		$allRoles = $wpRoles->roles;
		foreach ( $allRoles as $key => $wpRole ) {
			if ( $key === $role ) {
				$r = get_role( $key );
				if ( $r->has_cap( $capability ) ) {
					return true;
				}
			}
		}

		return false;
	}
}