README.md in createsend-3.1.0 vs README.md in createsend-3.1.1

@@ -187,10 +187,10 @@
 Bad request error: The CreateSend API responded with the following error - 304: Campaign Subject Required
 Error Code:    304
 Error Message: Campaign Subject Required
 ```
 
-### Expected input and output
+## Expected input and output
 The best way of finding out the expected input and output of a particular method in a particular class is to use the unit tests as a reference.
 
 For example, if you wanted to find out how to call the CreateSend::Subscriber.add method, you would look at the file test/subscriber_test.rb
 
 ```ruby