# File lib/rmail/header.rb, line 823
    def address_list_fetch(field_name)
      if values = fetch_all(field_name, nil)
        list = nil
        values.each { |value|
          if list
            list.concat(Address.parse(value))
          else
            list = Address.parse(value)
          end
        }
        if list and !list.empty?
          list
        end
      end or RMail::Address::List.new
    end