Add a function bz2.open(), to match gzip.open().
diff --git a/Doc/library/bz2.rst b/Doc/library/bz2.rst
index 893bb9b..d06a39a 100644
--- a/Doc/library/bz2.rst
+++ b/Doc/library/bz2.rst
@@ -14,7 +14,8 @@
The :mod:`bz2` module contains:
-* The :class:`BZ2File` class for reading and writing compressed files.
+* The :func:`.open` function and :class:`BZ2File` class for reading and
+ writing compressed files.
* The :class:`BZ2Compressor` and :class:`BZ2Decompressor` classes for
incremental (de)compression.
* The :func:`compress` and :func:`decompress` functions for one-shot
@@ -26,9 +27,37 @@
(De)compression of files
------------------------
+.. function:: open(filename, mode='r', compresslevel=9, encoding=None, errors=None, newline=None)
+
+ Open a bzip2-compressed file in binary or text mode, returning a :term:`file
+ object`.
+
+ As with the constructor for :class:`BZ2File`, the *filename* argument can be
+ an actual filename (a :class:`str` or :class:`bytes` object), or an existing
+ file object to read from or write to.
+
+ The *mode* argument can be any of ``'r'``, ``'rb'``, ``'w'``, ``'wb'``,
+ ``'a'``, or ``'ab'`` for binary mode, or ``'rt'``, ``'wt'``, or ``'at'`` for
+ text mode. The default is ``'rb'``.
+
+ The *compresslevel* argument is an integer from 1 to 9, as for the
+ :class:`BZ2File` constructor.
+
+ For binary mode, this function is equivalent to the :class:`BZ2File`
+ constructor: ``BZ2File(filename, mode, compresslevel=compresslevel)``. In
+ this case, the *encoding*, *errors* and *newline* arguments must not be
+ provided.
+
+ For text mode, a :class:`BZ2File` object is created, and wrapped in an
+ :class:`io.TextIOWrapper` instance with the specified encoding, error
+ handling behavior, and line ending(s).
+
+ .. versionadded:: 3.3
+
+
.. class:: BZ2File(filename, mode='r', buffering=None, compresslevel=9)
- Open a bzip2-compressed file.
+ Open a bzip2-compressed file in binary mode.
If *filename* is a :class:`str` or :class:`bytes` object, open the named file
directly. Otherwise, *filename* should be a :term:`file object`, which will