Preserve existing requirements

Cover with tests:

You must enter a comma delimited list of Dish Types with at least one selection
The output must print Dish Names in the following order: entrée, side, drink, dessert
If invalid selection is encountered, then print "error"
Ignore whitespace in the input
Each Dish Type is optional (i.e. can have zero if not entered in the input)
You can have multiple orders of potatoes (but still no more than 1 each of the other Dish Types)
If more than one Dish Type is entered, output it once, followed by "(xN)", e.g. "potato(x2)"

Salles-FA / test-practicum