save progress

src/Scanner/__Tests/StellaOps.Scanner.Emit.Tests/Pedigree/PedigreeBuilderTests.cs

@@ -2,6 +2,7 @@
 // Copyright (c) StellaOps. Licensed under the AGPL-3.0-or-later.
 // </copyright>
 
+using System.Collections.Immutable;
 using FluentAssertions;
 using Microsoft.Extensions.Time.Testing;
 using StellaOps.Scanner.Emit.Pedigree;