docs: private Map<String, List<String>> createUsernameRolesMap(final Iterable<String> roleList) {
          final Map<String, List<String>> usersRolesMap = new HashMap<>();
  
          for (final String role : roleList) {
              for (final String user : getUsersWithRole(role)) {
                  if (usersRolesMap.containsKey(user)) {
                      if (!usersRolesMap.get(user).contains(role)) {
                          usersRolesMap.get(user).add(role);
                      }
                  } else {
                      final List<String> list = new ArrayList<>(Collections.singletonList(role));
                      usersRolesMap.put(user, list);
                  }
              }
          }
  
          return usersRolesMap;
      }