public static void Rewrite(string assemblyLocation) {
            var assemblyDefinition = AssemblyDefinition.ReadAssembly(assemblyLocation);
            foreach (var type in assemblyDefinition.Modules.SelectMany(m => m.Types).Where(t => t.IsPublic)) {
                UnsealType(type);
            }
            SaveTestingAssembly(assemblyLocation, assemblyDefinition);
        }

        private static void UnsealType(TypeDefinition type) {
            type.IsSealed = false;
            foreach (var method in type.Methods.Where(m => m.IsPublic && !m.IsStatic && !m.IsConstructor)) {
                method.IsVirtual = true;
            }
            foreach (var nestedTypes in type.NestedTypes) {
                UnsealType(nestedTypes);
            }
        }

        private static void SaveTestingAssembly(string assemblyLocation, AssemblyDefinition assemblyDefinition) {
            assemblyDefinition.Name = new AssemblyNameDefinition(assemblyDefinition.Name.Name + ".ForTesting", assemblyDefinition.Name.Version);
            var newAssemblyPath = Path.Combine(Path.GetDirectoryName(assemblyLocation), Path.GetFileNameWithoutExtension(assemblyLocation) + ".ForTesting.dll");
            assemblyDefinition.Write(newAssemblyPath);
        }