Wraps an (optional) user callback to parse CommandHistoryEntry
    from a WebSocket data message

def _wrap_callback_parse_cmdhist_data(subscription, on_data, message):
    """
    Wraps an (optional) user callback to parse CommandHistoryEntry
    from a WebSocket data message
    """
    if (message.type == message.DATA and
            message.data.type == yamcs_pb2.CMD_HISTORY):
        entry = getattr(message.data, 'command')
        #pylint: disable=protected-access
        rec = subscription._process(entry)
        if on_data:
            on_data(rec)