@@ -80,6 +80,10 @@ internal static Type GetTypeByAlias(IntPtr op) {
         // This always returns a new reference. Note that the System.Decimal
         // type has no Python equivalent and converts to a managed instance.
         //====================================================================
+        internal static IntPtr ToPython<T>(T value)
+        {
+            return ToPython(value, typeof(T));
+        }
 
         internal static IntPtr ToPython(Object value, Type type) {
             IntPtr result = IntPtr.Zero;
 
@@ -447,6 +447,7 @@ static Interop() {
             pmap["bf_getcharbuffer"] = p["IntObjArgFunc"];
 
             pmap["__import__"] = p["TernaryFunc"];
+            pmap["__instancecheck__"] = p["BinaryFunc"];
         }
 
         internal static Type GetPrototype(string name) {
 
@@ -260,10 +260,30 @@ public static void tp_dealloc(IntPtr tp) {
             return;
         }
 
-
-
-
+        public static IntPtr __instancecheck__(IntPtr tp, IntPtr args)
+        {
+            ClassBase cb = GetManagedObject(tp) as ClassBase;
+
+            if (cb == null)
+                return Runtime.PyFalse;
+
+            using (PyList argsObj = new PyList(args))
+            {
+                if (argsObj.Length() != 1)
+                    return Exceptions.RaiseTypeError("Invalid parameter count");
+
+                PyObject arg = argsObj[0];
+                PyObject otherType = arg.GetPythonType();
+
+                if (Runtime.PyObject_TYPE(otherType.Handle) != PyCLRMetaType)
+                    return Runtime.PyFalse;
+
+                ClassBase otherCb = GetManagedObject(otherType.Handle) as ClassBase;
+                if (otherCb == null)
+                    return Runtime.PyFalse;
+
+                return Converter.ToPython(cb.type.IsAssignableFrom(otherCb.type));
+            }
+        }
     }
-
-
 }
@@ -300,7 +300,17 @@ internal static IntPtr CreateMetaType(Type impl) {
             flags |= TypeFlags.Managed;
             flags |= TypeFlags.HeapType;
             flags |= TypeFlags.HaveGC;
-            Marshal.WriteIntPtr(type, TypeOffset.tp_flags, (IntPtr)flags);
+            Marshal.WriteIntPtr(type, TypeOffset.tp_flags, (IntPtr)flags);
+
+            IntPtr fp = Interop.GetThunk(typeof(MetaType).GetMethod("__instancecheck__"));
+            IntPtr mdef = Runtime.PyMem_Malloc(5 * IntPtr.Size);
+            Marshal.WriteIntPtr(mdef, Marshal.StringToHGlobalAnsi("__instancecheck__"));
+            Marshal.WriteIntPtr(mdef, (1 * IntPtr.Size), fp);
+            Marshal.WriteIntPtr(mdef, (2 * IntPtr.Size), (IntPtr)0x0001); // METH_VARARGS
+            Marshal.WriteIntPtr(mdef, (3 * IntPtr.Size), IntPtr.Zero);
+            Marshal.WriteIntPtr(mdef, (4 * IntPtr.Size), IntPtr.Zero);
+
+            Marshal.WriteIntPtr(type, TypeOffset.tp_methods, mdef);
 
             Runtime.PyType_Ready(type);
Original file line number	Diff line number	Diff line change
@@ -447,6 +447,7 @@ static Interop() {
447	447	pmap["bf_getcharbuffer"] = p["IntObjArgFunc"];
448	448
449	449	pmap["__import__"] = p["TernaryFunc"];
	450	+ pmap["__instancecheck__"] = p["BinaryFunc"];
450	451	}
451	452
452	453	internal static Type GetPrototype(string name) {