def METHOD_NAME(
    self, client_manager: ClientManager
) -> Optional[Parameters]:
    """Initialize the (global) model parameters.
    Parameters
    ----------
    client_manager : ClientManager
        The client manager which holds all currently connected clients.
    Returns
    -------
    parameters : Optional[Parameters]
        If parameters are returned, then the server will treat these as the
        initial global model parameters.
    """