The class of a function can be either static or public.
b. A static function is available only to the test or module within which the function was defined.
c. Once you execute a public function, it is available to all tests, for as long as the test containing the function remains open. This is convenient when you want the function to be accessible from called tests. However, if you want to create a function that will be available to many tests, you should place it in a compiled module. The functions in a compiled module are available for the duration of the testing session.
d. If no class is explicitly declared, the function is assigned the default class, public.