Clarify acceptable values for BZ2File.__init__'s mode argument.
diff --git a/Lib/bz2.py b/Lib/bz2.py
index ae59407..d04731b 100644
--- a/Lib/bz2.py
+++ b/Lib/bz2.py
@@ -46,8 +46,8 @@
be opened. Otherwise, it should be a file object, which will be used to
read or write the compressed data.
- mode can be 'r' for reading (default), 'w' for (over)writing, or
- 'a' for appending.
+ mode can be 'r' for reading (default), 'w' for (over)writing, or 'a' for
+ appending. These can equivalently be given as 'rb', 'wb', and 'ab'.
buffering is ignored. Its use is deprecated.