diff -r edf669b13482 Doc/library/stdtypes.rst
--- a/Doc/library/stdtypes.rst	Tue Dec 23 16:28:28 2014 +0200
+++ b/Doc/library/stdtypes.rst	Tue Dec 23 19:20:54 2014 -0500
@@ -1944,22 +1944,22 @@
         "They're Bill's Friends."
 
 
-.. method:: str.translate(map)
-
-   Return a copy of the *s* where all characters have been mapped through the
-   *map* which must be a dictionary of Unicode ordinals (integers) to Unicode
-   ordinals, strings or ``None``.  Unmapped characters are left untouched.
-   Characters mapped to ``None`` are deleted.
+.. method:: str.translate(table)
+
+   Return a copy of the string in which each character has been
+   mapped through the given translation table.  The table must be
+   an object that implements lookup/indexing via :meth:`__getitem__`,
+   typically a :term:`mapping` or :term:`sequence`.  When indexed by
+   a Unicode ordinal (an integer), the table object can do any of the
+   following: return a Unicode ordinal or a string, to
+   map the character to one or more other characters; or
+   return ``None``, to delete the character from the return string; or
+   raise a :exc:`LookupError` exception, to
+   map the character to itself.
 
    You can use :meth:`str.maketrans` to create a translation map from
    character-to-character mappings in different formats.
 
-   .. note::
-
-      An even more flexible approach is to create a custom character mapping
-      codec using the :mod:`codecs` module (see :mod:`encodings.cp1251` for an
-      example).
-
 
 .. method:: str.upper()
 
diff -r edf669b13482 Objects/unicodeobject.c
--- a/Objects/unicodeobject.c	Tue Dec 23 16:28:28 2014 +0200
+++ b/Objects/unicodeobject.c	Tue Dec 23 19:20:54 2014 -0500
@@ -13065,10 +13065,12 @@
 PyDoc_STRVAR(translate__doc__,
              "S.translate(table) -> str\n\
 \n\
-Return a copy of the string S, where all characters have been mapped\n\
-through the given translation table, which must be a mapping of\n\
-Unicode ordinals to Unicode ordinals, strings, or None.\n\
-Unmapped characters are left untouched. Characters mapped to None\n\
+Return a copy of the string S in which each character has been mapped\n\
+through the given translation table. The table must implement
+lookup/indexing via __getitem__, for instance a dictionary or list,\n\
+mapping Unicode ordinals to\n\
+Unicode ordinals, strings, or None. If this operation raises\n\
+LookupError, the character is left untouched. Characters mapped to None\n\
 are deleted.");
 
 static PyObject*