code: public static ILockableEntityGroup findLockableGroup(String key, String lockOwner)
              throws GroupsException {
          LOGGER.trace("Invoking findLockableGroup for key='{}', lockOwner='{}'", key, lockOwner);
          return instance().ifindLockableGroup(key, lockOwner);
      }
docs: Returns a pre-existing <code>ILockableEntityGroup</code> or null if the group is not found.
  
  @param key String - the group key.
  @param lockOwner String - the owner of the lock, typically the user.
  @return org.apereo.portal.groups.ILockableEntityGroup