code: public boolean hasGroup(String groupName) {
          boolean result = false;
          for (Group item : getGroupsList()) {
              if (item.getName().equals(groupName)) {
                  result = true;
              }
          }
          return result;
      }
docs: Check if a group with the given groupName exists in the
  list or not.
  The check will be done case-sensitive.
  @param groupName The name we are searching for.
  @return true if the group has been found false otherwise.