diff --git a/lib/ext.js b/lib/ext.js
deleted file mode 100644
index b8a04a6..0000000
--- a/lib/ext.js
+++ /dev/null
@@ -1,18 +0,0 @@
-// batteries
-// Copyright 2010 - 2011 Sami Samhuri <sami@samhuri.net>
-
-exports.extend = function(obj, ext) {
-  Object.keys(ext).forEach(function(k) {
-    if (k in obj.prototype) return; // don't overwrite existing members
-    var wrapper = function() {
-      var fn = ext[k]
-        , args = [].slice.call(arguments)
-        ;
-      args.unshift(this);
-      return fn.apply(this, args);
-    };
-    Object.defineProperty(obj.prototype, k, {
-      get: function() { return wrapper; }
-    });
-  });
-};
diff --git a/lib/object.js b/lib/object.js
index 58facd7..adfc2b0 100644
--- a/lib/object.js
+++ b/lib/object.js
@@ -4,10 +4,11 @@
 var ObjectExt =
 { cmp: cmp
 , extend: extend
+, extendPrototype: extendPrototype
 }
 
 exports.extendNative = function() {
-  require('./ext').extend(Object, ObjectExt);
+  extendPrototype(Object, ObjectExt);
 };
 
 extend(module.exports, ObjectExt);
@@ -24,3 +25,25 @@ function extend(a, b) {
     a[k] = b[k];
   });
 }
+
+function extendPrototype(obj, ext) {
+  Object.keys(ext).forEach(function(k) {
+    // TODO remove this and just warn? ... no good solution for conflicts, needs a human
+    if (k in obj.prototype) return; // don't overwrite existing members
+    var val = ext[k];
+    if (typeof val === 'function') {
+      val = methodWrapper(val);
+    }
+    Object.defineProperty(obj.prototype, k, { value: val });
+  });
+}
+
+// Make a wrapper than passes `this` as the first argument, Python style. All
+// extension functions that can extend native types must follow this convention.
+function methodWrapper(fn) {
+  return function() {
+    var args = [].slice.call(arguments);
+    args.unshift(this);
+    return fn.apply(this, args);
+  };
+}