docs: def load_clients_file(filename, configuration_class=ClientConfiguration):
      """
      Loads client configurations from a YAML file.
  
      :param filename: YAML file name.
      :type filename: unicode | str
      :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]
      """
      with open(filename, 'r') as f:
          return load_clients(f, configuration_class=configuration_class)