code: def _lookup_vpc_count_min_max(session=None, **bfilter):
      
  
      if session is None:
          session = bc.get_reader_session()
  
      try:
          res = session.query(
              func.count(nexus_models_v2.NexusVPCAlloc.vpc_id),
              func.min(nexus_models_v2.NexusVPCAlloc.vpc_id),
              func.max(nexus_models_v2.NexusVPCAlloc.vpc_id),
          ).filter(nexus_models_v2.NexusVPCAlloc.switch_ip ==
                   bfilter['switch_ip']).one()
  
          count = res[0]
          sw_min = res[1]
          sw_max = res[2]
  
          return count, sw_min, sw_max
  
      except sa_exc.NoResultFound:
          pass
  
      raise c_exc.NexusVPCAllocNotFound(**bfilter)
docs: Look up count/min/max Nexus VPC Allocs for given switch.
  
      :param session: db session
      :param bfilter: filter for mappings query
      :returns: number of VPCs and min value if query gave a result,
               else raise NexusVPCAllocNotFound.