code: public List<CmsUser> getManageableUsers(CmsObject cms, String ouFqn, boolean includeSubOus, boolean includeWebusers)
      throws CmsException {
  
          List<CmsOrganizationalUnit> ous = getManageableOrgUnits(cms, ouFqn, includeSubOus, includeWebusers);
          List<CmsUser> users = new ArrayList<CmsUser>();
          Iterator<CmsOrganizationalUnit> it = ous.iterator();
          while (it.hasNext()) {
              CmsOrganizationalUnit orgUnit = it.next();
              users.addAll(OpenCms.getOrgUnitManager().getUsers(cms, orgUnit.getName(), false));
          }
          return users;
      }
docs: Returns all users of organizational units for which the current user has
  the {@link CmsRole#ACCOUNT_MANAGER} role.<p>
  
  @param cms the current cms context
  @param ouFqn the fully qualified name of the organizational unit
  @param includeSubOus if sub organizational units should be included in the search
  @param includeWebusers if webuser organizational units should be included in the search
  
  @return a list of {@link org.opencms.file.CmsUser} objects
  
  @throws CmsException if something goes wrong