code: def get_order(self):
          
          # first get the filtered attributes in order as they must appear
          # in the order_by first
          if not self.has_order:
              return None
          filter_order_clauses = OrderedDict([(filter_attr[0], None)
                                              for filter_attr in self._filters
                                              if isinstance(filter_attr, tuple)])
  
          # any order_by attribute that appears in the filters is ignored
          order_by_dict = self._order_by.copy()
          for filter_oc in filter_order_clauses.keys():
              direction = order_by_dict.pop(filter_oc, None)
              filter_order_clauses[filter_oc] = direction
  
          filter_order_clauses.update(
              order_by_dict)  # append any remaining order_by clause
  
          if filter_order_clauses:
              return ','.join(['{} {}'.format(attribute,
                                              direction if direction else '')
                              .strip()
                               for attribute, direction in
                               filter_order_clauses.items()])
          else:
              return None
docs: Returns the result order by clauses
  
          :rtype: str or None