Import the module <Literal>Generics</Literal> from the <Literal>lang</Literal> package.
This import brings into scope the data types <Literal>Unit</Literal>, <Literal>:*:</Literal>,
and <Literal>:+:</Literal>. (You don't need this import if you don't mention these
types explicitly; for example, if you are simply giving instance declarations.)
Import the module <Literal>Generics</Literal> from the <Literal>lang</Literal> package.
This import brings into scope the data types <Literal>Unit</Literal>, <Literal>:*:</Literal>,
and <Literal>:+:</Literal>. (You don't need this import if you don't mention these
types explicitly; for example, if you are simply giving instance declarations.)