diff --git a/MBS.Framework/Logic/Variable.cs b/MBS.Framework/Logic/Variable.cs
index d548309..016d729 100644
--- a/MBS.Framework/Logic/Variable.cs
+++ b/MBS.Framework/Logic/Variable.cs
@@ -39,7 +39,7 @@ namespace MBS.Framework.Logic
 		public string Name { get; set; } = null;
 		public Expression Expression { get; set; } = null;
 
-		public Variable(string name, Expression expression)
+		public Variable(string name, Expression expression = null)
 		{
 			Name = name;
 			Expression = expression;
diff --git a/MBS.Framework/MBS.Framework.csproj b/MBS.Framework/MBS.Framework.csproj
index 96cee59..99712db 100644
--- a/MBS.Framework/MBS.Framework.csproj
+++ b/MBS.Framework/MBS.Framework.csproj
@@ -10,7 +10,7 @@
     <ProductVersion>8.0.30703</ProductVersion>
     <SchemaVersion>2.0</SchemaVersion>
     <SignAssembly>true</SignAssembly>
-    <AssemblyOriginatorKeyFile>..\..\MichaelBecker.snk</AssemblyOriginatorKeyFile>
+    <AssemblyOriginatorKeyFile>..\..\Production.snk</AssemblyOriginatorKeyFile>
     <ReleaseVersion>4.0.2019.12</ReleaseVersion>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">