                      data: json,
                      httpMethod: "POST") {
                         (res: Result<JSON.Dict, BlockChainDB.QueryError>) in
-                        switch res {
-                        case .success: completion (Result.success(()))
-                        case .failure(let error):
-                            // Consider 302 or 404 errors as success - owing to a 'quirk'
-                            if case let QueryError.response (status) = error,
-                                (201 == status || 302 == status || 404 == status) {
-                                completion (Result.success(()))
-                            }
-                            else {
-                                completion (Result.failure(error))
-                            }
-                        }}
+                        // The completion expects Void on success; so map to `()` below
+                        completion (res.map { (json) in return () })
+        }
     }
 
     // Blocks

        }
    }

    private func sendRequest<T> (_ request: URLRequest, _ dataTaskFunc: DataTaskFunc, completion: @escaping (Result<T, QueryError>) -> Void) {
        dataTaskFunc (session, request) { (data, res, error) in
            guard nil == error else {
                completion (Result.failure(QueryError.submission (error!))) // NSURLErrorDomain

                return
            }

            guard responseSuccess.contains(res.statusCode) else {
                completion (Result.failure (QueryError.response(res.statusCode)))
                return
            }
