anchor.diff:          ..from = event.from
           ..to = event.to
           ..armies = event.armies);
  +    lastBattle = null;
   
       if (game.turnStep == TURN_STEP_FORTIFICATION) {
         nextPlayer();
  
positive.code:   _publish(EngineEvent event) {
      game.update(event);
      history.add(event);
      if (outputStream != null) {
        outputStream.add(event);
      }
    }
  
    /**
  
negative.code:   }
  
    /// Checks the number of armies bounds
    checkArmiesNumber(int armies, {int min, int max: null, String countryId, String action:
        'attack'}) {
      if (min != null && armies < min) throw new EngineException(
          "Can't $action with less than $min armies");
      if (max != null && armies > max) throw new EngineException(
          "Can't $action with more than $max armies");
  
      if(countryId != null) {
        /// Checks if there is enough armies in country to attack or to move
        checkCountryExists(countryId);
        if (game.countries[countryId].armies - armies < 1) throw
            new EngineException("There is not enough armies in country #${countryId}");
      }
    }
  
    /// Checks if countries are the same as the last attack
  