#6586: fix return/argument type doc for os.read() and os.write().
diff --git a/Doc/library/os.rst b/Doc/library/os.rst
index db96a56..206a15c 100644
--- a/Doc/library/os.rst
+++ b/Doc/library/os.rst
@@ -540,9 +540,9 @@
.. function:: read(fd, n)
- Read at most *n* bytes from file descriptor *fd*. Return a string containing the
+ Read at most *n* bytes from file descriptor *fd*. Return a bytestring containing the
bytes read. If the end of the file referred to by *fd* has been reached, an
- empty string is returned. Availability: Unix, Windows.
+ empty bytes object is returned. Availability: Unix, Windows.
.. note::
@@ -574,8 +574,8 @@
.. function:: write(fd, str)
- Write the string *str* to file descriptor *fd*. Return the number of bytes
- actually written. Availability: Unix, Windows.
+ Write the bytestring in *str* to file descriptor *fd*. Return the number of
+ bytes actually written. Availability: Unix, Windows.
.. note::