Document that varlist can be NULL.
diff --git a/Doc/api/concrete.tex b/Doc/api/concrete.tex
index 7e784c7..b00b915 100644
--- a/Doc/api/concrete.tex
+++ b/Doc/api/concrete.tex
@@ -1741,8 +1741,10 @@
PyObject *itemlist}
Sets the slice of \var{list} between \var{low} and \var{high} to the
contents of \var{itemlist}. Analogous to
- \code{\var{list}[\var{low}:\var{high}] = \var{itemlist}}. Returns
- \code{0} on success, \code{-1} on failure.
+ \code{\var{list}[\var{low}:\var{high}] = \var{itemlist}}.
+ The \var{itemlist} may be \NULL{}, indicating the assignment
+ of an empty list (slice deletion).
+ Returns \code{0} on success, \code{-1} on failure.
\end{cfuncdesc}
\begin{cfuncdesc}{int}{PyList_Sort}{PyObject *list}