How to extract dictionary single key-value pair in variables

Add another level, with a tuple (just the comma):

(k, v), = d.items()

or with a list:

[(k, v)] = d.items()

or pick out the first element:

k, v = d.items()[0]

The first two have the added advantage that they throw an exception if your dictionary has more than one key, and both work on Python 3 while the latter would have to be spelled as k, v = next(iter(d.items())) to work.

Demo:

>>> d = {'foo': 'bar'}
>>> (k, v), = d.items()
>>> k, v
('foo', 'bar')
>>> [(k, v)] = d.items()
>>> k, v
('foo', 'bar')
>>> k, v = d.items()[0]
>>> k, v
('foo', 'bar')
>>> k, v = next(iter(d.items()))  # Python 2 & 3 compatible
>>> k, v
('foo', 'bar')

items() returns a list of tuples so:

(k,v) = d.items()[0]

>>> d = {"a":1}
>>> [(k, v)] = d.items()
>>> k
'a'
>>> v
1

Or using next, iter:

>>> k, v = next(iter(d.items()))
>>> k
'a'
>>> v
1
>>>