code: function(protoProps, classProps) {
  			var child = inherits(this, protoProps, classProps);
  			child.extend = this.extend;
  			// a hack required to WSH inherit `toString` method
  			if (protoProps.hasOwnProperty('toString'))
  				child.prototype.toString = protoProps.toString;
  			return child;
  		}
docs: The self-propagating extend function for classes.
  Took it from Backbone
  @param {Object} protoProps
  @param {Object} classProps
  @returns {Object}