prefer to use if..end unless the condition is simple/compact

railties/guides/source/active_record_validations_callbacks.textile

@@ -1143,8 +1143,9 @@ Here's an example where we create a class with an +after_destroy+ callback for a
 <ruby>
 class PictureFileCallbacks
   def after_destroy(picture_file)
-    File.delete(picture_file.filepath)
-      if File.exists?(picture_file.filepath)
+    if File.exists?(picture_file.filepath)
+      File.delete(picture_file.filepath)
+    end
   end
 end
 </ruby>
@@ -1162,8 +1163,9 @@ Note that we needed to instantiate a new +PictureFileCallbacks+ object, since we
 <ruby>
 class PictureFileCallbacks
   def self.after_destroy(picture_file)
-    File.delete(picture_file.filepath)
-      if File.exists?(picture_file.filepath)
+    if File.exists?(picture_file.filepath)
+      File.delete(picture_file.filepath)
+    end
   end
 end
 </ruby>