diff --git a/callouts/callouts-gen.mako.hpp b/callouts/callouts-gen.mako.hpp
index 7d28a3a..285092e 100644
--- a/callouts/callouts-gen.mako.hpp
+++ b/callouts/callouts-gen.mako.hpp
@@ -14,7 +14,7 @@
 
 constexpr auto callouts =
 {
-% for key, value in sorted(calloutsMap.iteritems()):
+% for key, value in sorted(calloutsMap.items()):
     std::make_tuple("${key}", "${value}"),
 % endfor
 };