Print sorbet flavors

You're working for a restaurant and they're asking you to generate the sorbet menu.

Provide a script printing every possible sorbet duos from a given list of flavors.

Don't print recipes with twice the same flavor (no "Chocolate Chocolate"), and don't print twice the same recipe (if you print "Vanilla Chocolate", don't print "Chocolate Vanilla", or vice-versa).

The flavors are:

FLAVORS = [
    "Banana",
    "Chocolate",
    "Lemon",
    "Pistachio",
    "Raspberry",
    "Strawberry",
    "Vanilla",
]

Print one duo per line, and separate flavors by comas, so your output should look like:

Banana, Chocolate
Banana, Lemon
Banana, Pistachio
Banana, Raspberry
Banana, Strawberry
Banana, Vanilla
Chocolate, Lemon
…