code: function() {
  		if(this.init) { this.init.apply(this, arguments) }
  		for (var i=0, mixin; mixin = mixins[i]; i++) {
  			if (mixin.init) { mixin.init.apply(this) }
  		}
  	}
docs: cls is the actual class function. Classes may implement this.init = function(){ ... }, which gets called upon instantiation