text: define([
  	'matreshka_dir/core/var/isxdr'
  ], function(isXDR) {
  	"use strict";
  	return isXDR ? function(sought) {
  		var _this = this,
  			l = _this.length,
  			i, item,
  			isMK = sought && sought.isMK;
  
  		for (i = 0; i < l; i++) {
  			item = _this[i];
  			if (isMK ? sought.eq(item) : sought === item) {
  				return i;
  			}
  		}
  
  		return -1;
  	} : Array.prototype.indexOf;
  });
  