code: func (r *EchoRequest) GetSlotValue(slotName string) (string, error) {
  	slot, err := r.GetSlot(slotName)
  
  	if err != nil {
  		return "", err
  	}
  
  	return slot.Value, nil
  }
docs: // GetSlotValue is a convenience method for getting the value of the specified slot out of an EchoRequest
  // as a string. An error is returned if a slot with that value is not found in the request.