diff --git a/Doc/lib/emailutil.tex b/Doc/lib/emailutil.tex
index d4a7313..a5030d2 100644
--- a/Doc/lib/emailutil.tex
+++ b/Doc/lib/emailutil.tex
@@ -40,10 +40,10 @@
 \begin{verbatim}
 from email.Utils import getaddresses
 
-tos = msg.get_all('to')
-ccs = msg.get_all('cc')
-resent_tos = msg.get_all('resent-to')
-resent_ccs = msg.get_all('resent-cc')
+tos = msg.get_all('to', [])
+ccs = msg.get_all('cc', [])
+resent_tos = msg.get_all('resent-to', [])
+resent_ccs = msg.get_all('resent-cc', [])
 all_recipients = getaddresses(tos + ccs + resent_tos + resent_ccs)
 \end{verbatim}
 \end{funcdesc}