"""StrKeyDict always converts non-string keys to `str`

This is a variation of `strkeydict.StrKeyDict` implemented

as a `dict` built-in subclass (instead of a `UserDict` subclass)

Test for initializer: keys are converted to `str`.

>>> d = StrKeyDict([(2, 'two'), ('4', 'four')])

>>> sorted(d.keys())

['2', '4']

Tests for item retrieval using `d[key]` notation::

>>> d['2']

'two'

>>> d[4]

'four'

>>> d[1]

Traceback (most recent call last):

...

KeyError: '1'

Tests for item retrieval using `d.get(key)` notation::

>>> d.get('2')

'two'

>>> d.get(4)

'four'

>>> d.get(1, 'N/A')

'N/A'

Tests for the `in` operator::

>>> 2 in d

True

>>> 1 in d

False

Test for item assignment using non-string key::

>>> d[0] = 'zero'

>>> d['0']

'zero'

Tests for update using a `dict` or a sequence of pairs::

>>> d.update({6:'six', '8':'eight'})

>>> sorted(d.keys())

['0', '2', '4', '6', '8']

>>> d.update([(10, 'ten'), ('12', 'twelve')])

>>> sorted(d.keys())

['0', '10', '12', '2', '4', '6', '8']

>>> d.update([1, 3, 5])

Traceback (most recent call last):

...

TypeError: cannot unpack non-iterable int object

"""

class StrKeyDict(dict):

self.update(kwds)