docs: public Grantee addRole(HsqlName name) {
  
          if (map.containsKey(name.name)) {
              throw Error.error(ErrorCode.X_28503, name.name);
          }
  
          Grantee g = new Grantee(name, this);
  
          g.isRole = true;
  
          map.put(name.name, g);
          roleMap.add(name.name, g);
  
          return g;
      }