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: standalone.rb
    path of file: ./repos/metasploit-framework/lib/msfdb_helpers
    
    the code of the file until where you have to start completion: require 'msfdb_helpers/db_interface'
module MsfdbHelpers
  class Standalone < DbInte
    
    def initialize(options:, db_conf:, connection_string:)
      @options = options
      @db_conf = db_conf
      begin
        @conn = PG.connect(connection_string)
      rescue PG::ConnectionBad
        print_error('Could not connect to standalone PostgreSQL instance. Ensure that the connection string is valid, and that the database is accessible')
        raise
      end