== How to fix it

`Contains` is a method defined on the `ICollection<T>` interface and takes a `T item` argument. 
`Any` is an extension method defined on the `IEnumerable<T>` interface and takes a predicate argument. 
Therefore, calls with simple equality checks like `Any(x => x == item)` can be replaced by `Contains(item)`.

This applies to the following collection types:

* https://learn.microsoft.com/en-us/dotnet/api/system.collections.generic.hashset-1[HashSet<T>]
* https://learn.microsoft.com/en-us/dotnet/api/system.collections.generic.sortedset-1[SortedSet<T>]
* https://learn.microsoft.com/en-us/dotnet/api/system.collections.generic.list-1[List<T>]