normalize (REXML::Parsers::BaseParser)

    # File src/rexml/parsers/baseparser.rb, line 359
                            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