docs: def from_node(index, value):
          """
          >>> SyncState.from_node(1, None).leader is None
          True
          >>> SyncState.from_node(1, '{}').leader is None
          True
          >>> SyncState.from_node(1, '{').leader is None
          True
          >>> SyncState.from_node(1, '[]').leader is None
          True
          >>> SyncState.from_node(1, '{"leader": "leader"}').leader == "leader"
          True
          >>> SyncState.from_node(1, {"leader": "leader"}).leader == "leader"
          True
          """
          if isinstance(value, dict):
              data = value
          elif value:
              try:
                  data = json.loads(value)
                  if not isinstance(data, dict):
                      data = {}
              except (TypeError, ValueError):
                  data = {}
          else:
              data = {}
          return SyncState(index, data.get('leader'), data.get('sync_standby'))