def _organize_parameter(parameter):
    """
    Convert operation parameter message to its dict format.

    Args:
        parameter (OperationParameter): Operation parameter message.

    Returns:
        dict, operation parameter.
    """
    parameter_result = dict()
    parameter_keys = [
        'mapStr',
        'mapBool',
        'mapInt',
        'mapDouble',
    ]
    for parameter_key in parameter_keys:
        base_attr = getattr(parameter, parameter_key)
        parameter_value = dict(base_attr)
        # convert str 'None' to None
        for key, value in parameter_value.items():
            if value == 'None':
                parameter_value[key] = None
        parameter_result.update(parameter_value)
    # drop `mapStrList` and `strValue` keys in result parameter
    str_list_para = dict(getattr(parameter, 'mapStrList'))
    result_str_list_para = dict()
    for key, value in str_list_para.items():
        str_list_para_list = list()
        for str_ele in getattr(value, 'strValue'):
            str_list_para_list.append(str_ele)
        str_list_para_list = list(map(lambda x: None if x == '' else x, str_list_para_list))
        result_str_list_para[key] = str_list_para_list
    parameter_result.update(result_str_list_para)

    return parameter_result