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: follow_up_possible_check.rb
    path of file: ./repos/zammad/app/models/channel/filter
    
    the code of the file until where you have to start completion: # Copyright (C) 2012-2024 Zammad Foundation, https://zammad-foundation.org/

module Channel::Filter::FollowUpPossibleCheck

  def self.run(_channel, mail, _transaction_params)
    ticket_id = mail[:'x-zammad-ticket-id']
    return true if !ticket_id

    ticket = Ticket.lookup(id: ticket_id)
    return true if !ticket
    return true if !ticket.state.state_type.name.match?(%r{^(closed|merged|removed)}i)

    # For closed tickets, we
    
  def self.run(_channel, mail, _transaction_params)
    ticket_id = mail[:'x-zammad-ticket-id']
    return true if !ticket_id

    ticket = Ticket.lookup(id: ticket_id)
    return true if !ticket
    return true if !ticket.state.state_type.name.match?(%r{^(closed|merged|removed)}i)

    # For closed tickets, we are checking the follow-up configuration.
    #   In case follow-up is effective, we have to remove follow-up information.
    case ticket.group.follow_up_possible
    when 'new_ticket_after_certain_time'
      if !ticket.reopen_after_certain_time?
        mail[:subject] = ticket.subject_clean(mail[:subject])
        mail[:'x-zammad-ticket-id']     = nil
        mail[:'x-zammad-ticket-number'] = nil
      end