code: def get_items(self, page=1, order_by=None, filters=None):
          
          start = (page-1)*self.per_page
          query = self.get_query()
          if order_by is not None:
              query = query.order_by(self._get_field(order_by))
          if filters is not None:
              query = self._filter(query, filters)
          return query.offset(start).limit(self.per_page), self.count(query)
docs: Fetch database for items matching.
  
          Args:
              page (int):
                  which page will be sliced
                  slice size is ``self.per_page``.
              order_by (str):
                  a field name to order query by.
              filters (dict):
                  a ``filter name``: ``value`` dict.
  
          Returns:
              tuple with:
                  items, sliced by page*self.per_page
                  total items without slice