Extrinsic 15461-2

{
  "heartbeat": {
    "blockNumber": 15460,
    "sessionIndex": 257,
    "validatorsLen": 4,
    "authorityIndex": 3
  },
  "signature": "0x124c55e08a0d79f30f60d3d183ae8c447a899d070fac766a1d52f9289d942a662ece77612719a2f74478cf97300c112480e54b5b3b2851ecfe827819cc73f580"
}