Simplify an example based on comment from Thomas Holenstein <thomas@hex.ch>:
Do not use an extra flag variable to test only once in one subsequent if
statement.
diff --git a/Doc/lib/libcgi.tex b/Doc/lib/libcgi.tex
index 285c08f..8ab562d 100644
--- a/Doc/lib/libcgi.tex
+++ b/Doc/lib/libcgi.tex
@@ -89,10 +89,7 @@
\begin{verbatim}
form = cgi.FieldStorage()
-form_ok = 0
-if form.has_key("name") and form.has_key("addr"):
- form_ok = 1
-if not form_ok:
+if not (form.has_key("name") and form.has_key("addr")):
print "<H1>Error</H1>"
print "Please fill in the name and addr fields."
return