You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: notification_sms.rb
    path of file: ./repos/zammad/app/models/ticket/perform_changes/action
    
    the code of the file until where you have to start completion: # Copyright (C) 2012-2024 Zammad Foundation, https://zammad-foundation.org/

class Ticket::PerformChanges::Action::NotificationSms < Ticket::PerformChanges::Action

  def self.phase
    :after_save
  end

  def execute(...)
    send_sms_no
    
  def recipients_by_type(recipient_type)
    case recipient_type
    when 'article_last_sender'
      recipients_by_type_article_last_sender
    when 'ticket_customer'
      record.customer_id
    when 'ticket_owner'
      record.owner_id
    when 'ticket_agents'
      recipients_by_type_ticket_agents
    when %r{\Auserid_(\d+)\z}
      return $1 if User.exists?($1)

      Rails.logger.warn "Can't find configured #{origin} sms recipient user with ID '#{$1}'"
      nil
    else
      Rails.logger.error "Unknown sms notification recipient '#{recipient_type}'"
      nil
    end