Clarify docs for inspect.getargspec() that the fourth value is None when there
are no default arguments for the function.
diff --git a/Doc/lib/libinspect.tex b/Doc/lib/libinspect.tex
index 68ae67b..5cabb80 100644
--- a/Doc/lib/libinspect.tex
+++ b/Doc/lib/libinspect.tex
@@ -255,9 +255,9 @@
\var{args} is a list of the argument names (it may contain nested lists).
\var{varargs} and \var{varkw} are the names of the \code{*} and
\code{**} arguments or \code{None}.
- \var{defaults} is a tuple of default argument values; if this tuple
- has \var{n} elements, they correspond to the last \var{n} elements
- listed in \var{args}.
+ \var{defaults} is a tuple of default argument values or None if there are no
+ default arguments; if this tuple has \var{n} elements, they correspond to
+ the last \var{n} elements listed in \var{args}.
\end{funcdesc}
\begin{funcdesc}{getargvalues}{frame}