code: def _lookup_vpc_allocs(query_type, session=None, order=None, **bfilter):
      
  
      if session is None:
          session = bc.get_reader_session()
  
      if order:
          query_method = getattr(session.query(
              nexus_models_v2.NexusVPCAlloc).filter_by(**bfilter).order_by(
                  order),
              query_type)
      else:
          query_method = getattr(session.query(
              nexus_models_v2.NexusVPCAlloc).filter_by(**bfilter), query_type)
  
      try:
          vpcs = query_method()
          if vpcs:
              return vpcs
      except sa_exc.NoResultFound:
          pass
  
      raise c_exc.NexusVPCAllocNotFound(**bfilter)
docs: Look up 'query_type' Nexus VPC Allocs matching the filter.
  
      :param query_type: 'all', 'one' or 'first'
      :param session: db session
      :param order: select what field to order data
      :param bfilter: filter for mappings query
      :returns: VPCs if query gave a result, else
               raise NexusVPCAllocNotFound.