Part of SF patch #1513870 (the still relevant part) -- add reduce() to
functools, and adjust docs etc.
diff --git a/Doc/lib/libfunctools.tex b/Doc/lib/libfunctools.tex
index 33a6f52..034143a 100644
--- a/Doc/lib/libfunctools.tex
+++ b/Doc/lib/libfunctools.tex
@@ -51,6 +51,19 @@
\end{verbatim}
\end{funcdesc}
+\begin{funcdesc}{reduce}{function, sequence\optional{, initializer}}
+ Apply \var{function} of two arguments cumulatively to the items of
+ \var{sequence}, from left to right, so as to reduce the sequence to
+ a single value. For example, \code{reduce(lambda x, y: x+y, [1, 2,
+ 3, 4, 5])} calculates \code{((((1+2)+3)+4)+5)}. The left argument,
+ \var{x}, is the accumulated value and the right argument, \var{y},
+ is the update value from the \var{sequence}. If the optional
+ \var{initializer} is present, it is placed before the items of the
+ sequence in the calculation, and serves as a default when the
+ sequence is empty. If \var{initializer} is not given and
+ \var{sequence} contains only one item, the first item is returned.
+\end{funcdesc}
+
\begin{funcdesc}{update_wrapper}
{wrapper, wrapped\optional{, assigned}\optional{, updated}}
Update a wrapper function to look like the wrapped function. The optional