#7000: document "sep" in capwords. Add a few tests
diff --git a/Doc/library/string.rst b/Doc/library/string.rst
index 52aa41c..9a13dc6 100644
--- a/Doc/library/string.rst
+++ b/Doc/library/string.rst
@@ -585,12 +585,14 @@
They are not available as string methods.
-.. function:: capwords(s)
+.. function:: capwords(s[, sep])
- Split the argument into words using :func:`split`, capitalize each word using
- :func:`capitalize`, and join the capitalized words using :func:`join`. Note
- that this replaces runs of whitespace characters by a single space, and removes
- leading and trailing whitespace.
+ Split the argument into words using :meth:`str.split`, capitalize each word
+ using :meth:`str.capitalize`, and join the capitalized words using
+ :meth:`str.join`. If the optional second argument *sep* is absent
+ or ``None``, runs of whitespace characters are replaced by a single space
+ and leading and trailing whitespace are removed, otherwise *sep* is used to
+ split and join the words.
.. function:: maketrans(from, to)