"""StrKeyDict0 converts non-string keys to `str` on lookup

# BEGIN STRKEYDICT0_TESTS

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

    >>> d = StrKeyDict0([('2', 'two'), ('4', 'four')])
    >>> 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

# END STRKEYDICT0_TESTS
"""

# BEGIN STRKEYDICT0

import collections


class StrKeyDict0(collections.UserDict):  # <1>

    def __missing__(self, key):
        if isinstance(key, str):  # <2>
            raise KeyError(key)
        return self[str(key)]  # <3>

    def __contains__(self, key):
        return str(key) in self.data  # <3>

# END STRKEYDICT0