To establish a conformance relationship between the Catalog class and the <Catalog> protocol, follow these steps:
When you complete the connection, you should see methods appear in the
Catalog class design figure to show that it conforms to the
<Catalog> protocol.
Now select Display Options>Method Name Only from the
pop-up menu of the Catalog class figure. This turns off the Method
Name Only toggle so you can see the complete method signatures.
The method signatures include specifications of the types of the parameters and the return values of the methods. A plus sign (+) before a method signature indicates that the method is specified (it is taken from the protocol the class conforms to). Parentheses around the method name indicate that the method is unimplemented, meaning that no real method implementation exists in the underlying Smalltalk class.