def __setitem__(self, key, value):
        """Associate 'value' with 'key'. If 'key' already exists, but
        in different case, it will be replaced."""
        k = key.lower()
        self._dict[k] = (key, value)
Associate 'value' with 'key'. If 'key' already exists, but
        in different case, it will be replaced.
recipes/Python/66315_Caseinsensitive_Dictionary/recipe-66315.py