diff --git a/ogn/commands/logbook.py b/ogn/commands/logbook.py
index 98b4650..2471469 100644
--- a/ogn/commands/logbook.py
+++ b/ogn/commands/logbook.py
@@ -142,11 +142,20 @@ def show(airport_name, latitude, longitude, altitude):
 
     print('--- Logbook (%s) ---' % airport_name)
 
-    none_datetime_replacer = lambda datetime_object: '--:--:--' if datetime_object is None else datetime_object.time()
-    none_track_replacer = lambda track_object: '--' if track_object is None else round(track_object / 10.0)
-    none_timedelta_replacer = lambda timedelta_object: '--:--:--' if timedelta_object is None else timedelta_object
-    none_registration_replacer = lambda registration_object, address: '[' + address + ']' if registration_object is None else registration_object
-    none_aircraft_replacer = lambda aircraft_object: '(unknown)' if aircraft_object is None else aircraft_object
+    def none_datetime_replacer(datetime_object):
+        '--:--:--' if datetime_object is None else datetime_object.time()
+
+    def none_track_replacer(track_object):
+        '--' if track_object is None else round(track_object / 10.0)
+
+    def none_timedelta_replacer(timedelta_object):
+        '--:--:--' if timedelta_object is None else timedelta_object
+
+    def none_registration_replacer(registration_object, address):
+        '[' + address + ']' if registration_object is None else registration_object
+
+    def none_aircraft_replacer(aircraft_object):
+        '(unknown)' if aircraft_object is None else aircraft_object
 
     for [reftime, address, takeoff, takeoff_track, landing, landing_track, duration, registration, aircraft] in logbook_query.all():
         print('%10s   %8s (%2s)   %8s (%2s)   %8s   %8s   %s' % (