setPizzaTopping: async (event, context) => {          
  context.clearItemValue("PizzaTopping");             
  context.setItemValue("PizzaTopping", event.PizzaTopping);
  //set a confirmation message. The boolean value true at its end sets the "keepTurn"
  //behavior. True means that the bot continues with the next bag item, not waiting 
  //for user input
  context.addMessage("Great. Now that we've got this sorted, let us continue.", true);          
}