Add a function to compute a class's method resolution order.  This is
easy for 2.2 new-style classes, but trickier for classic classes, and
different approaches are needed "depending".  The function will allow
later code to treat all flavors of classes uniformly.
diff --git a/Lib/test/test_inspect.py b/Lib/test/test_inspect.py
index 130fa8e..dbb6609 100644
--- a/Lib/test/test_inspect.py
+++ b/Lib/test/test_inspect.py
@@ -213,3 +213,23 @@
         os.unlink(fname)
     except:
         pass
+
+# Test classic-class method resolution order.
+class A:    pass
+class B(A): pass
+class C(A): pass
+class D(B, C): pass
+
+expected = (D, B, A, C)
+got = inspect.getmro(D)
+test(expected == got, "expected %r mro, got %r", expected, got)
+
+# The same w/ new-class MRO.
+class A(object):    pass
+class B(A): pass
+class C(A): pass
+class D(B, C): pass
+
+expected = (D, B, C, A, object)
+got = inspect.getmro(D)
+test(expected == got, "expected %r mro, got %r", expected, got)