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: parseexception.rb
    path of file: ./repos/truffleruby/lib/gems/gems/rexml-3.2.5/lib/rexml
    
    the code of the file until where you have to start completion: # frozen_string_literal: false
module REXML
  class ParseException < RuntimeError
    attr_accessor :source, :parser, :continued_exception

    def initialize( message, source=nil, parser=nil, exception=nil )
      sup
    
    def to_s
      # Quote the original exception, if there was one
      if @continued_exception
        err = @continued_exception.inspect
        err << "\n"
        err << @continued_exception.backtrace.join("\n")
        err << "\n...\n"
      else
        err = ""
      end