README.md in dry-data-0.1.0 vs README.md in dry-data-0.2.0

@@ -115,10 +115,10 @@
 ```
 
 You can define your own optional types too:
 
 ``` ruby
-maybe_string = Dry::Data["nil"] | Dry::Data["string"]
+maybe_string = Dry::Data["optional"] | Dry::Data["string"]
 
 maybe_string[nil]
 # => None
 
 maybe_string[nil].fmap(&:upcase)