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: baseparser.rb
    path of file: ./repos/ruby-packer/ruby/lib/rexml/parsers
    
    the code of the file until where you have to start completion: # frozen_string_literal: false
require_relative '../parseexception'
require_relative '../undefinednamespaceexception'
require_relative '../source'
require 'set'
require "strscan"

module REXML
  module
    
      def normalize( input, entities=nil, entity_filter=nil )
        copy = input.clone
        # Doing it like this rather than in a loop improves the speed
        copy.gsub!( EREFERENCE, '&amp;' )
        entities.each do |key, value|
          copy.gsub!( value, "&#{key};" ) unless entity_filter and
                                      entity_filter.include?(entity)
        end if entities
        copy.gsub!( EREFERENCE, '&amp;' )
        DEFAULT_ENTITIES.each do |key, value|
          copy.gsub!( value[3], value[1] )
        end
        copy
      end

      # Unescapes all possible entities
      def unnormalize( string, entities=nil, filter=nil )
        rv = string.clone
        rv.gsub!( /\r\n?/, "\n" )
        matches = rv.scan( REFERENCE_RE )
        return rv if matches.size == 0
        rv.gsub!( /&#0*((?:\d+)|(?:x[a-fA-F0-9]+));/ ) {
          m=$1
          m = "0#{m}" if m[0] == ?x
          [Integer(m)].pack('U*')
        }
        matches.collect!{|x|x[0]}.compact!
        if matches.size > 0
          matches.each do |entity_reference|
            unless filter and filter.include?(entity_reference)
              entity_value = entity( entity_reference, entities )
              if entity_value
                re = /&#{entity_reference};/
                rv.gsub!( re, entity_value )
              else
                er = DEFAULT_ENTITIES[entity_reference]
                rv.gsub!( er[0], er[2] ) if er
              end
            end
          end