Merge
diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst
index be6f2ec..d621e87 100644
--- a/Doc/library/functions.rst
+++ b/Doc/library/functions.rst
@@ -1237,8 +1237,8 @@
.. function:: round(number[, ndigits])
Return the floating point value *number* rounded to *ndigits* digits after
- the decimal point. If *ndigits* is omitted, it returns the nearest integer
- to its input. Delegates to ``number.__round__(ndigits)``.
+ the decimal point. If *ndigits* is omitted or is ``None``, it returns the
+ nearest integer to its input. Delegates to ``number.__round__(ndigits)``.
For the built-in types supporting :func:`round`, values are rounded to the
closest multiple of 10 to the power minus *ndigits*; if two multiples are