code: public boolean hasPermissionForUser(String user, String... permission) {
          List<String> params = new ArrayList<>();
  
          params.add(user);
          Collections.addAll(params, permission);
  
          return hasPolicy(params);
      }
docs: hasPermissionForUser determines whether a user has a permission.
  
  @param user the user.
  @param permission the permission, usually be (obj, act). It is actually the rule without the subject.
  @return whether the user has the permission.