lib/eighty_legs/eighty_format.rb in 80legs-0.2.2 vs lib/eighty_legs/eighty_format.rb in 80legs-0.2.3

@@ -1,10 +1,10 @@
 module EightyLegs
   class EightyFormat
     def initialize(filename_or_io)
       if filename_or_io.is_a?(String)
         initialize_with_filename(filename_or_io)
-      elsif filename_or_io.is_a?(IO)
+      elsif filename_or_io.respond_to?(:read)
         initialize_with_io(filename_or_io)
       else
         raise TypeError.new(filename_or_io.class)
       end
       check_for_classid_and_version()