Expose Py_Py3kWarningFlag as sys.py3kwarning as discussed in #1504
Also added a warning.warnpy3k() as convenient method for Python 3.x related deprecation warnings.
diff --git a/Lib/new.py b/Lib/new.py
index a3298b6..1a5c11f 100644
--- a/Lib/new.py
+++ b/Lib/new.py
@@ -3,9 +3,9 @@
 This module is no longer required except for backward compatibility.
 Objects of most types can now be created by calling the type object.
 """
-from warnings import warn as _warn
-_warn("The 'new' module is not supported in 3.x, use the 'types' module "
-    "instead.", DeprecationWarning, 2)
+from warnings import warnpy3k as _warnpy3k
+_warnpy3k("The 'new' module is not supported in 3.x, use the 'types' module "
+    "instead.", stacklevel=2)
 
 from types import ClassType as classobj
 from types import FunctionType as function