code: function (childView, el) {
  				if (RUNTIME_CHECKS) {
  					if (!(childView instanceof View)) {
  						throw '"childView" argument must be a BFF View';
  					}
  					if (arguments.length > 1 && !(el === false || el instanceof HTMLElement)) {
  						throw '"el" argument must be an HTMLElement or the boolean value false';
  					}
  				}
  
  				this.__private.childViews.push(childView);
  				el !== false && (el || this.el).appendChild(childView.el);
  				return childView;
  			}
docs: Adds another view as a child to the view. A child view will be automatically added to this view's root element and destroyed whenever its parent view is destroyed.
  @instance
  @arg {module:bff/view} childView - The view that will be added to the list of this view's children.
  @arg {HTMLElement|boolean} [optional] - An element to which the child view's root element will be appended. If not specified, it will be appended to this view's root element. Can also be `false`, in which case the child view will not be appended to anything.