      an optional `name` or `container` implicitly references the default name or container,
      but in this case, it means _any_ name or container.
      */
-    public static func unregister(name: AnyHashable? = nil, container: AnyHashable? = nil) -> Int {
+    @discardableResult public static func unregister(name: AnyHashable? = nil, container: AnyHashable? = nil) -> Int {
         if name == nil && container == nil {
             return clear()
         } else {

     an optional `name` or `container` implicitly references the default name or container,
     but in this case, it means _any_ name or container.
     */
    public static func unregister<T>(type: T.Type, name: AnyHashable? = nil, container: AnyHashable? = nil) -> Int {
        return unregister(keys: filter(type: type, name: name, container: container))
    }
    

     
     - returns: The number of registrations removed
     */
    @discardableResult public static func clear() -> Int {
        return lock.write {
            let count = registrations.count
            registrations = [:]
