code: private String calculateStringToSignV1(Map<String, List<String>> parameters) {
          StringBuilder data = new StringBuilder();
          SortedMap<String, List<String>> sorted =
              new TreeMap<String, List<String>>(String.CASE_INSENSITIVE_ORDER);
          sorted.putAll(parameters);
  
          for (Map.Entry<String, List<String>> entry : sorted.entrySet()) {
              for (String value : entry.getValue()) {
                  data.append(entry.getKey())
                      .append(value);
              }
          }
  
          return data.toString();
      }
docs: Calculates string to sign for signature version 1.
  
  @param parameters
  request parameters
  
  @return String to sign