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

# encoding: utf-8

class Channel::EmailParser
  include Channel::EmailHelper

  PROZESS_TIME_MAX = 180
  EMAIL_REGEX = %r{.+@.+}
  RECIPIENT_FIELDS = %w[to cc delivered-to x-original-to envelope-to].freeze
  SENDER_FIELDS = %w[from reply-to return-path sender].freeze
  EXCESSIVE_LINKS_MSG = __('This message cannot be displayed because it contains over 5,000 links. Download the raw message below and open it via an Email client if you still wish to view it.').freeze
  MESSAGE_STRUCT = Struct.new(:from_display_name, :subject, :msg_size).freeze

  UNPROCESSABLE_MAIL_DIRECTORY = Rails.root.join('var/spool/unprocessable_mail')

=begin

  parser = Channel::EmailParser.new
  mail = parser.parse(msg_as_string)

  mail = {
    from:              'Some Name <some@example.com>',
    from_email:        'some@example.com',
    from_loca
    
  def set_attributes_by_x_headers(item_object, header_name, mail, suffix = false)

    # loop all x-zammad-header-* headers
    item_object.attributes.each_key do |key|

      # ignore read only attributes
      next if key == 'updated_by_id'
      next if key == 'created_by_id'

      # check if id exists
      key_short = key[ key.length - 3, key.length ]
      if key_short == '_id'
        key_short = key[ 0, key.length - 3 ]
        header = "x-zammad-#{header_name}-#{key_short}"
        if suffix
          header = "x-zammad-#{header_name}-#{suffix}-#{key_short}"
        end

        # only set value on _id if value/reference lookup exists
        if mail[header.to_sym]

          Rails.logger.info "set_attributes_by_x_headers header #{header} found #{mail[header.to_sym]}"
          item_object.class.reflect_on_all_associations.map do |assoc|

            next if assoc.name.to_s != key_short

            Rails.logger.info "set_attributes_by_x_headers found #{assoc.class_name} lookup for '#{mail[header.to_sym]}'"
            item = assoc.class_name.constantize
            assoc_object = nil
            if item.new.respond_to?(:name)
              assoc_object = item.lookup(name: mail[header.to_sym])
            end
            if !assoc_object && item.new.respond_to?(:login)
              assoc_object = item.lookup(login: mail[header.to_sym])
            end