1{ 2 "topology_description": { 3 "type": "ReplicaSetNoPrimary", 4 "servers": [ 5 { 6 "address": "a:27017", 7 "type": "Unknown" 8 }, 9 { 10 "address": "b:27017", 11 "type": "Unknown" 12 } 13 ] 14 }, 15 "read_preference": { 16 "mode": "Nearest", 17 "maxStalenessSeconds": 1 18 }, 19 "error": true 20}