code: function _uniqContentEquals(aIterator, bIterator, stackA, stackB) {
  	  var a = _arrayFromIterator(aIterator);
  	  var b = _arrayFromIterator(bIterator);
  	
  	  function eq(_a, _b) {
  	    return _equals(_a, _b, stackA.slice(), stackB.slice());
  	  }
  	
  	  // if *a* array contains any element that is not included in *b*
  	  return !_containsWith(function (b, aItem) {
  	    return !_containsWith(eq, aItem, b);
  	  }, b, a);
  	}
docs: private _uniqContentEquals function.
  That function is checking equality of 2 iterator contents with 2 assumptions
  - iterators lengths are the same
  - iterators values are unique
  
  false-positive result will be returned for comparision of, e.g.
  - [1,2,3] and [1,2,3,4]
  - [1,1,1] and [1,2,3]