diff --git a/lib/Array/prototype/common-left.js b/lib/Array/prototype/common-left.js
index <HASH>..<HASH> 100644
--- a/lib/Array/prototype/common-left.js
+++ b/lib/Array/prototype/common-left.js
@@ -4,13 +4,11 @@
 
 var every         = Array.prototype.every
   , call          = Function.prototype.call
-  , assertNotNull = require('../../assert-not-null')
   , toArray       = require('../../Object/to-array')
   , sortMethod    = call.bind(require('../../Object/get-compare-by')('length'));
 
 module.exports = function (list) {
 	var lists, r, l;
-	assertNotNull(this);
 
 	lists = [this].concat(toArray(arguments)).sort(sortMethod);
 	l = r = lists[0].length >>> 0;
Input arguments are already validated by sortMethod