Index: Objects/listobject.c
===================================================================
--- Objects/listobject.c	(revision 73521)
+++ Objects/listobject.c	(working copy)
@@ -2328,6 +2328,29 @@
 	return NULL;
 }
 
+static PyObject *
+listswap(PyListObject *self, PyObject *v)
+{
+	PyListObject *vl, tmp;
+	if (!PyList_Check(v)) {
+		PyErr_SetString(PyExc_TypeError, "list.swap(x): x must be a list");
+		return 0;
+	}
+	vl = (PyListObject *)v;
+	tmp.ob_size = self->ob_size;
+	tmp.ob_item = self->ob_item;
+	tmp.allocated = self->allocated;
+
+	self->ob_size = vl->ob_size;
+	self->ob_item = vl->ob_item;
+	self->allocated = vl->allocated;
+
+	vl->ob_size = tmp.ob_size;
+	vl->ob_item = tmp.ob_item;
+	vl->allocated = tmp.allocated;
+	Py_RETURN_NONE;
+}
+
 static int
 list_traverse(PyListObject *o, visitproc visit, void *arg)
 {
@@ -2478,6 +2501,8 @@
 PyDoc_STRVAR(sort_doc,
 "L.sort(cmp=None, key=None, reverse=False) -- stable sort *IN PLACE*;\n\
 cmp(x, y) -> -1, 0, 1");
+PyDoc_STRVAR(swap_doc,
+"L.swap(list) -- swap the contents of L with list");
 
 static PyObject *list_subscript(PyListObject*, PyObject*);
 
@@ -2494,6 +2519,7 @@
 	{"count",	(PyCFunction)listcount,   METH_O, count_doc},
 	{"reverse",	(PyCFunction)listreverse, METH_NOARGS, reverse_doc},
 	{"sort",	(PyCFunction)listsort, 	  METH_VARARGS | METH_KEYWORDS, sort_doc},
+	{"swap",	(PyCFunction)listswap,	  METH_O, swap_doc},
  	{NULL,		NULL}		/* sentinel */
 };