Building Tilemap Animations in code require AnimationController

I am building a Tiled.org TMX parser (I know there are ones that exist and I'm using one of them, but I'm extending it to allow for Tiled animations) and I've run into a problem where I cannot programmatically create an Animation Controller.

Let's say I have the following snippet of code:

 Animator newAnimator = (Animator)tilePrefabObj.AddComponent<Animator> ();
 newAnimator.runtimeAnimatorController = (RuntimeAnimatorController)RuntimeAnimatorController.Instantiate (Resources.Load ("Artwork/Sprites/sprite_0"));
 
 SpriteRenderer sr = tilePrefabObj.AddComponent<SpriteRenderer> ();
 SourceData sd = gid2sprite [tileGID.Value];
 Sprite source = (Sprite)sprites.First (s => s.name.Equals (sd.spriteName));
 
 sr.sprite = source;
 sr.sortingOrder = 0;
 sr.color = new Color (1, 1, 1, 1.0f);

This works just fine and I can see that my prefab contains the Animator component and that its Runtime Animation Controller is set to the sprite_0 prefab.

What if I want to reference multiple sprites and create an Animation Controller programmatically and set the runtimeAnimationController to that instead -- rather than use an existing Resource that already exists?

I can't find any documentation on creating a simple Animation Controller that contains a handful of different sprites in order to create an animated sprite.