ByteBuddy: How to declare a class with a custom method inside another class

I'm trying to dynamically create a class which extends a class ServerPing, inside this class there is a static class called Serializer, I want to override its method "a" and returns my own JsonElement. The problem is that I don't know how to edit a static class inside another class using bytebuddy.

Here is what it could look like (but defineClassInside doesn't exist):

        Class<?> serverPingSerializerClone = new ByteBuddy()
                .subclass(serverPingClass)
                .defineClassInside("Serializer",
                        new ByteBuddy().subclass(ServerPing.Serializer.class)
                                .method(ElementMatchers.named("a")
                                        .and(ElementMatchers.returns(JsonElement.class)
                                                .and(ElementMatchers.takesArguments(3))))
                                .intercept(FixedValue.value(exampleResponse))
                                .make())
                .make()
                .load(Core.class.getClassLoader(), ClassLoadingStrategy.Default.WRAPPER).getLoaded();```