code: function() {
      var dependencies = this.__all__.reduce(function(all, mixin) {
        return mixin instanceof Mixin.__class__ ?
          all.concat(mixin.__mixins__()) :
          all;
      }, []);
      return dependencies
        .concat([this]);
    }
docs: Create a flattened array of all mixin objects (including this object)
  that compose this mixin.
  
  The difference between this and {@link-to __flatten__} is that this will
  only include Mixin objects while `__flatten__` will include any properties
  that will be mixed in.
  
  @method
  @private
  @return {Array.<Mixin>} The mixins