code: def query_by_args(self, pre_search_condition=None, **kwargs):
          
          if pre_search_condition and not isinstance(pre_search_condition, OrderedDict):
              raise TypeError(
                  "Parameter 'pre_search_condition' must be an OrderedDict.")
          # extract requisite parameters from kwargs
          draw = ensure(int, kwargs.get('draw', [0])[0], 0)
  
          # just implement the get_query_dict function
          query_dict = self.get_query_dict(**kwargs)
          order_key = self.get_order_key(**kwargs)
  
          # get the model from the serializer parameter
          model_class = self.serializer.Meta.model
          # get the objects
          queryset = model_class.objects
  
          # apply the pre search condition if it exists
          if pre_search_condition:
              queryset = self.filtering(queryset, pre_search_condition)
          else:
              queryset = queryset.all()
  
          # number of the total records
          total = queryset.count()
  
          # if the query dict not empty, then apply the query dict
          if query_dict:
              queryset = self.filtering(queryset, query_dict)
  
          # number of the records after applying the query
          count = queryset.count()
  
          # order the queryset
          queryset = queryset.order_by(order_key)
  
          # slice the queryset
          queryset = self.slicing(queryset, **kwargs)
          return {'items': queryset, 'count': count, 'total': total, 'draw': draw}
docs: intends to process the queries sent by data tables package in frontend.
          The model_cls indicates the model class, get_query_dict is a function
          implemented by you, such that it can
          return a query dictionary, in which the key is the query keyword in str
          form and the value is the queried value
  
          :param pre_search_condition: None/OrderedDict: dictionary contains
            filter conditions which should be processed before applying the filter
            dictionary from user. None, if no pre_search_condition provided.
          :param kwargs: QueryDict: contains query parameters
          :return: dict: contains total records number, queryset of the filtered
            instances, size of this queryset