add python reference impl of MethodObject and ComputedAttribute

src/ComputedAttribute/__init__.py

@@ -1 +1,23 @@
-from _ComputedAttribute import *
+from ExtensionClass import Base
+
+
+class ComputedAttribute(Base):
+    """ComputedAttribute(callable) -- Create a computed attribute"""
+
+    def __init__(self, func, level=0):
+        if level > 0:
+            func = ComputedAttribute(func, level - 1)
+        self.callable = func
+        self.level = level
+
+    def __of__(self, inst):
+        func = self.__dict__['callable']
+        if self.level:
+            return func
+        return func(inst)
+
+
+try:
+    from _ComputedAttribute import *
+except:
+    pass

src/MethodObject/__init__.py

@@ -1 +1,24 @@
-from _MethodObject import *
+import new
+from ExtensionClass import Base
+
+
+class Method(Base):
+    """Base class for objects that want to be treated as methods
+
+    The method class provides a method, __of__, that
+    binds an object to an instance.  If a method is a subobject
+    of an extension-class instance, the the method will be bound
+    to the instance and when the resulting object is called, it
+    will call the method and pass the instance in addition to
+    other arguments.  It is the responsibility of Method objects
+    to implement (or inherit) a __call__ method.
+    """
+
+    def __of__(self, inst):
+        return new.instancemethod(self, inst)
+
+
+try:
+    from _MethodObject import *
+except:
+    pass