Fix typo.
diff --git a/Doc/ext.tex b/Doc/ext.tex
index 57223d4..729f5d1 100644
--- a/Doc/ext.tex
+++ b/Doc/ext.tex
@@ -695,7 +695,7 @@
Indicates that the remaining arguments in the Python argument list are
optional. The \C{} variables corresponding to optional arguments should
be initialized to their default value --- when an optional argument is
-not specified, \cfuntion{PyArg_ParseTuple()} does not touch the contents
+not specified, \cfunction{PyArg_ParseTuple()} does not touch the contents
of the corresponding \C{} variable(s).
\item[\samp{:}]
diff --git a/Doc/ext/ext.tex b/Doc/ext/ext.tex
index 57223d4..729f5d1 100644
--- a/Doc/ext/ext.tex
+++ b/Doc/ext/ext.tex
@@ -695,7 +695,7 @@
Indicates that the remaining arguments in the Python argument list are
optional. The \C{} variables corresponding to optional arguments should
be initialized to their default value --- when an optional argument is
-not specified, \cfuntion{PyArg_ParseTuple()} does not touch the contents
+not specified, \cfunction{PyArg_ParseTuple()} does not touch the contents
of the corresponding \C{} variable(s).
\item[\samp{:}]