Some useful advice, even to someone not writing in Scala, especially sections like published interfaces. > When defining an interface to a package someone else

Some useful advice, even to someone not writing in Scala, especially sections like published interfaces. > When defining an interface to a package someone else will use... > 1. The simplest interface to a package is static method with standard types > 2. Next, static methods that take/return custom types, presumably with methods > 3. Next, is needing the user to instantiate some classes > 4. Lastly, is needing the user to inherit from some classes