What does the [Flags] attribute mean for enums in C#?

Hello, colleagues! I'm learning C# and came across the [Flags] attribute before an enum declaration. I read several articles but still don't fully understand why it's needed. Here's an example I found: ```csharp [Flags] public enum Days { None = 0, Monday = 1, Tuesday = 2, Wednesday = 4, Thursday = 8, Friday = 16, Saturday = 32, Sunday = 64 } ``` I understand that the values are set as powers of two (1, 2, 4, 8...), but I don't understand: 1. What exactly does the [Flags] attribute do? The code compiles without it too. 2. How to properly combine values? I tried writing `Days weekend = Days.Saturday | Days.Sunday;`, but I'm not sure if that's correct. 3. How to then check if a specific day is contained in such a combination? For example, whether Saturday is in the weekend variable?