Instantiate ImportRequest
        :param cfg: request configuration, should consist of request description (url and parameters) and response for parsing result
        :param login:
        :param pswd:
        :param request_type: TYPE_GET_SINGLE_OBJECT or TYPE_GET_LIST = 'list'
        :return: ImportRequest instance

def factory(cfg, login, pswd, request_type):
        """
        Instantiate ImportRequest
        :param cfg: request configuration, should consist of request description (url and parameters) and response for parsing result
        :param login:
        :param pswd:
        :param request_type: TYPE_GET_SINGLE_OBJECT or TYPE_GET_LIST = 'list'
        :return: ImportRequest instance
        """
        if request_type == ImportRequest.TYPE_GET_LIST:
            return ListImportRequest(cfg, login, pswd)
        elif request_type == ImportRequest.TYPE_GET_SINGLE_OBJECT:
            return SingleObjectImportRequest(cfg, login, pswd)
        else:
            raise NotImplementedError('Not supported request type - {}'.format(request_type))