diff --git a/01-Core/Jinget.Core/ExtensionMethods/Reflection/PropertiesExtensions.cs b/01-Core/Jinget.Core/ExtensionMethods/Reflection/PropertiesExtensions.cs
index e384e94..ff69f66 100644
--- a/01-Core/Jinget.Core/ExtensionMethods/Reflection/PropertiesExtensions.cs
+++ b/01-Core/Jinget.Core/ExtensionMethods/Reflection/PropertiesExtensions.cs
@@ -32,7 +32,7 @@ private static IEnumerable<PropertyInfo> GetDeclaredProperties(Type t) =>
     /// </summary>
     /// <param name="type">The type to check.</param>
     /// <returns>True if the type is a simple type; otherwise, false.</returns>
-    public static bool IsSimpleType(Type? t)
+    public static bool IsSimpleType(this Type? t)
     {
         while (true)
         {
diff --git a/Tests/Jinget.Core.Tests/ExtensionMethods/Reflection/PropertiesExtensionsTests.cs b/Tests/Jinget.Core.Tests/ExtensionMethods/Reflection/PropertiesExtensionsTests.cs
index 20840fb..016759c 100644
--- a/Tests/Jinget.Core.Tests/ExtensionMethods/Reflection/PropertiesExtensionsTests.cs
+++ b/Tests/Jinget.Core.Tests/ExtensionMethods/Reflection/PropertiesExtensionsTests.cs
@@ -10,41 +10,41 @@ struct MyStruct { public int Value; }
     [TestMethod]
     public void IsSimpleType_PrimitiveTypes_ReturnsTrue()
     {
-        Assert.IsTrue(PropertiesExtensions.IsSimpleType(typeof(int)));
-        Assert.IsTrue(PropertiesExtensions.IsSimpleType(typeof(bool)));
-        Assert.IsTrue(PropertiesExtensions.IsSimpleType(typeof(char)));
-        Assert.IsTrue(PropertiesExtensions.IsSimpleType(typeof(double)));
+        Assert.IsTrue(typeof(int).IsSimpleType());
+        Assert.IsTrue(typeof(bool).IsSimpleType());
+        Assert.IsTrue(typeof(char).IsSimpleType());
+        Assert.IsTrue(typeof(double).IsSimpleType());
     }
 
     [TestMethod]
     public void IsSimpleType_DecimalStringGuidDateTimeByteArrayEnum_ReturnsTrue()
     {
-        Assert.IsTrue(PropertiesExtensions.IsSimpleType(typeof(decimal)));
-        Assert.IsTrue(PropertiesExtensions.IsSimpleType(typeof(string)));
-        Assert.IsTrue(PropertiesExtensions.IsSimpleType(typeof(Guid)));
-        Assert.IsTrue(PropertiesExtensions.IsSimpleType(typeof(DateTime)));
-        Assert.IsTrue(PropertiesExtensions.IsSimpleType(typeof(byte[])));
-        Assert.IsTrue(PropertiesExtensions.IsSimpleType(typeof(MyEnum)));
+        Assert.IsTrue(typeof(decimal).IsSimpleType());
+        Assert.IsTrue(typeof(string).IsSimpleType());
+        Assert.IsTrue(typeof(Guid).IsSimpleType());
+        Assert.IsTrue(typeof(DateTime).IsSimpleType());
+        Assert.IsTrue(typeof(byte[]).IsSimpleType());
+        Assert.IsTrue(typeof(MyEnum).IsSimpleType());
     }
 
     [TestMethod]
     public void IsSimpleType_NullableTypes_ReturnsTrue()
     {
-        Assert.IsTrue(PropertiesExtensions.IsSimpleType(typeof(int?)));
-        Assert.IsTrue(PropertiesExtensions.IsSimpleType(typeof(decimal?)));
-        Assert.IsTrue(PropertiesExtensions.IsSimpleType(typeof(Guid?)));
-        Assert.IsTrue(PropertiesExtensions.IsSimpleType(typeof(DateTime?)));
-        Assert.IsTrue(PropertiesExtensions.IsSimpleType(typeof(MyEnum?)));
+        Assert.IsTrue(typeof(int?).IsSimpleType());
+        Assert.IsTrue(typeof(decimal?).IsSimpleType());
+        Assert.IsTrue(typeof(Guid?).IsSimpleType());
+        Assert.IsTrue(typeof(DateTime?).IsSimpleType());
+        Assert.IsTrue(typeof(MyEnum?).IsSimpleType());
     }
 
     [TestMethod]
     public void IsSimpleType_NonSimpleTypes_ReturnsFalse()
     {
-        Assert.IsFalse(PropertiesExtensions.IsSimpleType(typeof(object)));
-        Assert.IsFalse(PropertiesExtensions.IsSimpleType(typeof(MyClass)));
-        Assert.IsFalse(PropertiesExtensions.IsSimpleType(typeof(MyStruct)));
-        Assert.IsFalse(PropertiesExtensions.IsSimpleType(typeof(int[,]))); // multidimensional array
-        Assert.IsFalse(PropertiesExtensions.IsSimpleType(typeof(int[]))); // one dimensional array that is not byte[]
+        Assert.IsFalse(typeof(object).IsSimpleType());
+        Assert.IsFalse(typeof(MyClass).IsSimpleType());
+        Assert.IsFalse(typeof(MyStruct).IsSimpleType());
+        Assert.IsFalse(typeof(int[,]).IsSimpleType()); // multidimensional array
+        Assert.IsFalse(typeof(int[]).IsSimpleType()); // one dimensional array that is not byte[]
     }
 
     [TestMethod]
@@ -76,7 +76,7 @@ public void Should_return_all_writable_primitive_properties()
         var result = typeof(TestClass).GetWritableProperties();
 
         Assert.IsNotNull(result);
-        Assert.IsTrue(result.Any());
+        Assert.IsTrue(result.Count != 0);
         Assert.AreEqual(expectedResult.First(), result.First());
     }
 }
\ No newline at end of file