I'm not sure there is one. They're useful in C# as a way of defining a function within another function (which sometimes makes for more readable code). For exam

I'm not sure there is one. They're useful in C# as a way of defining a function within another function (which sometimes makes for more readable code). For example: public int CountRelevantItems(IEnumerable<Thing> things) { // Non-trivial filter that you don't want in a where lamdba Func<Thing, bool> isRelevant = (t) => { ... } return things.Where(t => isRelevant(t)).Count() } But in Python you can already define functions inside of functions so you have a better solution: def CountRelevantThings(things): def isRelevant(thing): ... return len(filter(isRelevant, things))