docs: def load_clients(stream, configuration_class=ClientConfiguration):
      """
      Loads client configurations from a YAML document stream.
  
      :param stream: YAML stream.
      :type stream: file
      :param configuration_class: Class of the configuration object to create.
      :type configuration_class: class
      :return: A dictionary of client configuration objects.
      :rtype: dict[unicode | str, dockermap.map.config.client.ClientConfiguration]
      """
      client_dict = yaml.safe_load(stream)
      if isinstance(client_dict, dict):
          return {client_name: configuration_class(**client_config)
                  for client_name, client_config in six.iteritems(client_dict)}
      raise ValueError("Valid configuration could not be decoded.")