lib/writeexcel/olewriter.rb in writeexcel-0.4.0 vs lib/writeexcel/olewriter.rb in writeexcel-0.4.1

@@ -25,10 +25,10 @@
   attr_reader :root_start, :size_allowed
   attr_accessor :biff_only, :internal_fh
 
   # Accept an IO or IO-like object or a filename (as a String)
   def initialize(arg)
-    if arg.kind_of?(String)
+    if arg.respond_to?(:to_str)
       @io = File.open(arg, "w")
     else
       @io = arg
     end
     @io.binmode if @io.respond_to?(:binmode)