                  "UNSET"
                                      "ECONOMICAL"
                                      "CONSERVATIVE"
     }
3. iswitness                          (boolean, optional, default=depends on heuristic tests) Whether the transaction hex is a serialized witness transaction.
                                      If iswitness is not present, heuristic tests will be used in decoding.
                                      If true, only witness deserialization will be tried.
                