Extension methods in Rules errors due to ambiguous call

// In TestPlugin.Build.cs

using System;
using UnrealBuildTool;

public class TestPlugin : ModuleRules
{
    public TestPlugin(ReadOnlyTargetRules Target) : base(Target)
    {
        PCHUsage = ModuleRules.PCHUsageMode.UseExplicitOrSharedPCHs;
         
        this.PrintExternal();
    }
}

public static class TestExternalClass
{
    public static void PrintExternal(this ModuleRules Rule)
    {
        Console.WriteLine($"Called from TestExternalClass: {Rule.EngineDirectory}");
    }
}