Ok, its been a struggle! My final proposition:

```javascript
/**
* Removes all child instances from the child list of the container.
*
* @method removeChildren
* @param beginIndex {Number} The beginning position. Predefined value is 0.
* @param endIndex {Number} The ending position. Predefined value is children's array length.
*/
PIXI.DisplayObjectContainer.prototype.removeChildren = function(beginIndex, endIndex)
{
    var begin = beginIndex || 0;
    var end = endIndex || this.children.length;
    var range = end - begin;

    if (range > 0 && range <= end)
    {
        var removed = this.children.splice(begin, range);
        for (var i = removed.length - 1; i >= 0; i--) {
            var child = removed[i];
            if(this.stage)child.removeStageReference();
            child.parent = undefined;
        }
    }
    else
    {
        throw new Error( 'Range Error, numeric values are outside the acceptable range' );
    }
};
```