Python and how to get the instance name of a variable

I needed the name of an instance in order to do some error reporting. I'm very lucky that each of these things I need to report on will only have one instance.

So of course, first thing I did was ask Google. And after a couple of weeks of checking now and again, I have been unable to find any solutions already published. I found a lot of "instances don't have names!", which clearly isn't true, but makes sense from the perspective that the instance name is a pointer to the thing, and there's no backwards pointing property in the thing being pointed at.

But as with most things, there's always a way. And it turns out that in python, it's actually pretty straightforward:

import gc


def instance_names(self):
    referrers = gc.get_referrers(self)
    result = []
    dict_of_things = {}
    for item in referrers:
        if isinstance(item, dict):
            dict_of_things = item
    for k, v in dict_of_things.items():
        if v == self:
            result.append(k)
    if not result:
        result = ['unnamed instance']
    return result

Returns a list of all matching instance names. Now it's possible to create an instance without a name, such as via a generator or a lambda, and I haven't tested what it will return in those cases, as that wasn't what I needed this for. It also fails for getting the name of a function, but that can gotten in other ways.

I hope this helps someone! :)