docs: private String parseParams(ParameterSet params, JSONObject obj) throws Exception
      {
          if (params.size() < 2) {
              return "@SnapshotDelete expects 2 or 3 arguments, received " + params.size();
          }
          String[] paths = null;
          Object paramList[] = params.toArray();
          try {
              paths = (String[])(ParameterConverter.tryToMakeCompatible(
                          String[].class,
                          paramList[0]));
          }
          catch (Exception e) {
              return e.getMessage();
          }
  
          if (paths == null || paths.length == 0) {
              return "No paths supplied";
          }
  
          for (String path : paths) {
              if (path == null || path.trim().isEmpty()) {
                  return "A path was null or the empty string";
              }
          }
  
          String[] nonces = null;
          try {
              nonces = (String[])(ParameterConverter.tryToMakeCompatible(
                          String[].class,
                          paramList[1]));
          }
          catch (Exception e) {
              return e.getMessage();
          }
  
          if (nonces == null || nonces.length == 0) {
              return "No nonces supplied";
          }
  
          for (String nonce : nonces) {
              if (nonce == null || nonce.trim().isEmpty()) {
                  return "A nonce was null or the empty string";
              }
          }
  
          if (paths.length != nonces.length) {
              return "A path must be provided for every nonce";
          }
          String stype = SnapshotPathType.SNAP_PATH.toString();
          if (params.size() > 2) {
              stype = (String )(ParameterConverter.tryToMakeCompatible(
                          String.class,
                          paramList[2]));
          }
          // Dupe SNAPSHOTSCAN as the subselector in case we consolidate later
          obj.put("subselector", "SNAPSHOTDELETE");
          obj.put("interval", false);
          obj.put("paths", paths);
          obj.put(SnapshotUtil.JSON_PATH_TYPE, stype);
          obj.put("nonces", nonces);
  
          return null;
      }