code: public CommandAuthorization find(String chargingStationId, String userIdentity, Class commandClass) {
          CommandAuthorizationId id = new CommandAuthorizationId(chargingStationId, userIdentity, commandClass);
  
          EntityManager em = getEntityManager();
          try {
              return em.find(CommandAuthorization.class, id);
          } finally {
              em.close();
          }
      }
docs: Finds {@code CommandAuthorization} based on charging station id, user identity and command class.
  
  @param chargingStationId    charging station identifier.
  @param userIdentity         user identity (user name).
  @param commandClass         command class.
  @return command authorization if it exists in the repository.