lib/axlsx/workbook/workbook_views.rb in caxlsx-3.4.1 vs lib/axlsx/workbook/workbook_views.rb in caxlsx-4.0.0

@@ -1,5 +1,7 @@
+# frozen_string_literal: true
+
 module Axlsx
   # a simple types list of BookView objects
   class WorkbookViews < SimpleTypedList
     # creates the book views object
     def initialize
@@ -7,10 +9,10 @@
     end
 
     # Serialize to xml
     # @param [String] str
     # @return [String]
-    def to_xml_string(str = '')
+    def to_xml_string(str = +'')
       return if empty?
 
       str << "<bookViews>"
       each { |view| view.to_xml_string(str) }
       str << '</bookViews>'