def load_dict(self, source, namespace='', make_namespaces=False):
        ''' Import values from a dictionary structure. Nesting can be used to
            represent namespaces.

            >>> ConfigDict().load_dict({'name': {'space': {'key': 'value'}}})
            {'name.space.key': 'value'}
        '''
        stack = [(namespace, source)]
        while stack:
            prefix, source = stack.pop()
            if not isinstance(source, dict):
                raise TypeError('Source is not a dict (r)' % type(key))
            for key, value in source.items():
                if not isinstance(key, str):
                    raise TypeError('Key is not a string (%r)' % type(key))
                full_key = prefix + '.' + key if prefix else key
                if isinstance(value, dict):
                    stack.append((full_key, value))
                    if make_namespaces:
                        self[full_key] = self.Namespace(self, full_key)
                else:
                    self[full_key] = value
        return self
Import values from a dictionary structure. Nesting can be used to
            represent namespaces.

            >>> ConfigDict().load_dict({'name': {'space': {'key': 'value'}}})
            {'name.space.key': 'value'}