code: private Evse getEvseByIdentifier(ChargingStationType chargingStationType, int identifier) {
          for (Evse evse:chargingStationType.getEvses()) {
              if(identifier == evse.getIdentifier()) {
                  return evse;
              }
          }
          return null;
      }
docs: Gets a Evse by identifier.
  
  @param chargingStationType    charging station type.
  @param identifier             evse identifier.
  @return evse or null if not found.