onal, default=false) If true, any signatures in the input will be discarded and conversion
                    will continue. If false, RPC will fail if any signatures are present.
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.
                    If fal