code: static List<String> flaggedKeyValues(final String flagName, @Nullable Map<?, ?> keyValueMapping) {
      List<String> result = Lists.newArrayList();
      if (keyValueMapping != null && keyValueMapping.size() > 0) {
        for (Map.Entry<?, ?> entry : keyValueMapping.entrySet()) {
          result.addAll(string(flagName, entry.getKey() + "=" + entry.getValue()));
        }
  
        return result;
      }
  
      return Collections.emptyList();
    }
docs: Produces a flagged key/value pair list given a flag name and a {@link Map}.
  
  @return {@code [--flagName, key1=value1, --flagName, key2=value2, ...]} or {@code []} if
  keyValueMapping=empty/null