<PackageReference Include="NUnit" Version="3.0.0" />

CollectionOperator

public abstract class CollectionOperator : PrefixOperator
Abstract base for operators that indicate how to apply a constraint to items in a collection.
namespace NUnit.Framework.Constraints { public abstract class CollectionOperator : PrefixOperator { protected CollectionOperator() { left_precedence = 1; right_precedence = 10; } } }