function format() {
			if (customFormatter) {
				return customFormatter.apply(null, arguments);
			}

			return inspect.apply(inspect, arguments);
		}
Public: Extend target in place with all (own) properties from sources in-order. Thus, last source will
        override properties in previous sources. Define the properties as non enumerable.

@param {object} target - The Object to extend
@param {object[]} sources - Objects to copy properties from.

@returns {object} the extended target