Universal JavaScript console log script

console_log.js

// usage: log('inside coolFunc', this, arguments);
// paulirish.com/2009/log-a-lightweight-wrapper-for-consolelog/
window.log = function f() {
	log.history = log.history || [];
	log.history.push(arguments);
	if (this.console) {
		var args = arguments,
			newarr;
		args.callee = args.callee.caller;
		newarr = [].slice.call(args);
		if (typeof console.log === 'object') log.apply.call(console.log, console, newarr);
		else console.log.apply(console, newarr);
	}
};

// make it safe to use console.log always
(function(a) {
	function b() {}
	for (var c = "assert,count,debug,dir,dirxml,error,exception,group,groupCollapsed,groupEnd,info,log,markTimeline,profile,profileEnd,time,timeEnd,trace,warn".split(","), d; !! (d = c.pop());) {
		a[d] = a[d] || b;
	}
})(function() {
	try {
		console.log();
		return window.console;
	} catch(a) {
		return (window.console = {});
	}
} ());

Hello...
I have a question... I found this code in a old web page that I manage. What is the purpose of this code?