Getting the name of a variable as a string

I already read How to get a function name as a string?.

How can I do the same for a variable? As opposed to functions, Python variables do not have the __name__ attribute.

In other words, if I have a variable such as:

foo = dict()
foo['bar'] = 2

I am looking for a function/attribute, e.g. retrieve_name, where:

>>> retrieve_name(foo)
'foo'

This is in order to create a DataFrame in Pandas from this list, where the column names are given by the names of the actual dictionaries:

# List of dictionaries for my DataFrame
list_of_dicts = [n_jobs, users, queues, priorities]
columns = [retrieve_name(d) for d in list_of_dicts]