Basic Trope: A TV show with a not very diverse cast.
Straight: Sally and Friends, a lighthearted sitcom, has an entirely white main cast.
The series is many seasons long, and not one nonwhite person ever shows up. Even in the background.
All characters look almost identical, with the same skin tone, hair color, eye color, etc.
The characters travel all over the world, and on every continent every single person is Caucasian.
Even the pets are white.
Downplayed: The main cast of Sally and Friends is all white, but a few background and/or very minor characters are played by nonwhite actors.
The setting of the series is a city or region that is known for not being very ethnically diverse.
Alternately, the series is set in a time during severe segregation, so you wouldn't expect to see a bunch of white kids hanging out with one black guy.
Inverted: The main cast of Sally and Friends is a highly diverse Five-Token Band, consisting of an African-American girl, a Jewish girl, a Japanese boy, a Hispanic boy, an Amerindian girl, and the Token White guy in a wheelchair.
Defied: The series is about accepting differences, racial and otherwise.
Discussed: "Why are we so...white?"
Conversed: "God, don't you hate how these sitcoms always have a cast that's either all white or all black? Maybe that made sense in The Sixties, but today it's just ridiculous!"
Implied: A couple of white protagonists are the only two people shown on camera, and while they do talk to some unseen characters, those unseen characters have ... very similar voices to the shown characters, leading to the induction that they too are of European descent.
Deconstructed: A group of American townspeople become very concerned about their lack of diversity. Turns out it was set up during the segregation days and never blended.
Reconstructed: But as they live in a very white state — Idaho, Utah, Vermont, Montana, Maine, North Dakota, New Hampshire — a lack of minorities is not unusual. They get on with their lives in their middle-class white suburb.