The easiest is to never use .keys() or .iterkeys(), and always iterate over the bare dict: for k in dict: ... if k in dict: ... If yo

The easiest is to never use .keys() or .iterkeys(), and always iterate over the bare dict: for k in dict: ... if k in dict: ... If you do need a list of keys, list(dict) has the advantage of working in both Python 2 and 3.