diff --git a/openlp/plugins/songs/forms/editsongform.py b/openlp/plugins/songs/forms/editsongform.py
index b1a22f1cf..cfe183db6 100644
--- a/openlp/plugins/songs/forms/editsongform.py
+++ b/openlp/plugins/songs/forms/editsongform.py
@@ -112,7 +112,8 @@ class EditSongForm(QtWidgets.QDialog, Ui_EditSongDialog, RegistryProperties):
         Generically load a set of objects into a cache and a combobox.
         """
         objects = self.manager.get_all_objects(cls)
-        objects.sort(key=lambda object: get_natural_key(object.name))
+        get_key = lambda object: get_natural_key(object.name)
+        objects.sort(key=get_key)
         combo.clear()
         combo.addItem('')
         for obj in objects:
@@ -346,7 +347,8 @@ class EditSongForm(QtWidgets.QDialog, Ui_EditSongDialog, RegistryProperties):
         Load the authors from the database into the combobox.
         """
         authors = self.manager.get_all_objects(Author)
-        authors.sort(key=lambda author: get_natural_key(author.display_name))
+        get_author_key = lambda author: get_natural_key(author.display_name)
+        authors.sort(key=get_author_key)
         self.authors_combo_box.clear()
         self.authors_combo_box.addItem('')
         self.authors = []
@@ -384,7 +386,8 @@ class EditSongForm(QtWidgets.QDialog, Ui_EditSongDialog, RegistryProperties):
         self.theme_combo_box.clear()
         self.theme_combo_box.addItem('')
         self.themes = theme_list
-        self.themes.sort(key=lambda theme: get_natural_key(theme))
+        get_theme_key = lambda theme: get_natural_key(theme)
+        self.themes.sort(key=get_theme_key)
         self.theme_combo_box.addItems(theme_list)
         set_case_insensitive_completer(self.themes, self.theme_combo_box)
 
diff --git a/openlp/plugins/songs/forms/songexportform.py b/openlp/plugins/songs/forms/songexportform.py
index ee35ea7e5..fbf909552 100644
--- a/openlp/plugins/songs/forms/songexportform.py
+++ b/openlp/plugins/songs/forms/songexportform.py
@@ -213,7 +213,8 @@ class SongExportForm(OpenLPWizard):
         # Load the list of songs.
         self.application.set_busy_cursor()
         songs = self.plugin.manager.get_all_objects(Song)
-        songs.sort(key=lambda song: song.sort_key)
+        get_song_key = lambda song: song.sort_key
+        songs.sort(key=get_song_key)
         for song in songs:
             # No need to export temporary songs.
             if song.temporary:
diff --git a/openlp/plugins/songs/forms/songmaintenanceform.py b/openlp/plugins/songs/forms/songmaintenanceform.py
index 6089c94e7..52c84acbd 100644
--- a/openlp/plugins/songs/forms/songmaintenanceform.py
+++ b/openlp/plugins/songs/forms/songmaintenanceform.py
@@ -123,7 +123,8 @@ class SongMaintenanceForm(QtWidgets.QDialog, Ui_SongMaintenanceDialog, RegistryP
         """
         self.authors_list_widget.clear()
         authors = self.manager.get_all_objects(Author)
-        authors.sort(key=lambda author: get_natural_key(author.display_name))
+        get_author_key = lambda author: get_natural_key(author.display_name)
+        authors.sort(key=get_author_key)
         for author in authors:
             if author.display_name:
                 author_name = QtWidgets.QListWidgetItem(author.display_name)
@@ -138,7 +139,8 @@ class SongMaintenanceForm(QtWidgets.QDialog, Ui_SongMaintenanceDialog, RegistryP
         """
         self.topics_list_widget.clear()
         topics = self.manager.get_all_objects(Topic)
-        topics.sort(key=lambda topic: get_natural_key(topic.name))
+        get_topic_key = lambda topic: get_natural_key(topic.name)
+        topics.sort(key=get_topic_key)
         for topic in topics:
             topic_name = QtWidgets.QListWidgetItem(topic.name)
             topic_name.setData(QtCore.Qt.UserRole, topic.id)
@@ -150,7 +152,8 @@ class SongMaintenanceForm(QtWidgets.QDialog, Ui_SongMaintenanceDialog, RegistryP
         """
         self.song_books_list_widget.clear()
         books = self.manager.get_all_objects(Book)
-        books.sort(key=lambda book: get_natural_key(book.name))
+        get_book_key = lambda book: get_natural_key(book.name)
+        books.sort(key=get_book_key)
         for book in books:
             book_name = QtWidgets.QListWidgetItem('%s (%s)' % (book.name, book.publisher))
             book_name.setData(QtCore.Qt.UserRole, book.id)
diff --git a/openlp/plugins/songs/lib/mediaitem.py b/openlp/plugins/songs/lib/mediaitem.py
index 2c483a48a..c43a23781 100644
--- a/openlp/plugins/songs/lib/mediaitem.py
+++ b/openlp/plugins/songs/lib/mediaitem.py
@@ -261,7 +261,8 @@ class SongMediaItem(MediaManagerItem):
         log.debug('display results Song')
         self.save_auto_select_id()
         self.list_view.clear()
-        search_results.sort(key=lambda song: song.sort_key)
+        get_song_key = lambda song: song.sort_key
+        search_results.sort(key=get_song_key)
         for song in search_results:
             # Do not display temporary songs
             if song.temporary:
@@ -285,9 +286,11 @@ class SongMediaItem(MediaManagerItem):
         """
         log.debug('display results Author')
         self.list_view.clear()
-        search_results.sort(key=lambda author: get_natural_key(author.display_name))
+        get_author_key = lambda author: get_natural_key(author.display_name)
+        search_results.sort(key=get_author_key)
         for author in search_results:
-            author.songs.sort(key=lambda song: song.sort_key)
+            get_song_key = lambda song: song.sort_key
+            author.songs.sort(key=get_song_key)
             for song in author.songs:
                 # Do not display temporary songs
                 if song.temporary:
@@ -306,8 +309,8 @@ class SongMediaItem(MediaManagerItem):
         """
         log.debug('display results Book')
         self.list_view.clear()
-        search_results.sort(key=lambda songbook_entry:
-                            (get_natural_key(songbook_entry.songbook.name), get_natural_key(songbook_entry.entry)))
+        get_songbook_key = lambda songbook_entry:(get_natural_key(songbook_entry.songbook.name), get_natural_key(songbook_entry.entry))
+        search_results.sort(key=get_songbook_key)
         for songbook_entry in search_results:
             # Do not display temporary songs
             if songbook_entry.song.temporary:
@@ -326,9 +329,11 @@ class SongMediaItem(MediaManagerItem):
         """
         log.debug('display results Topic')
         self.list_view.clear()
-        search_results.sort(key=lambda topic: get_natural_key(topic.name))
+        get_topic_key = lambda topic: get_natural_key(topic.name)
+        search_results.sort(key=get_topic_key)
         for topic in search_results:
-            topic.songs.sort(key=lambda song: song.sort_key)
+            get_song_key = lambda song: song.sort_key
+            topic.songs.sort(key=get_song_key)
             for song in topic.songs:
                 # Do not display temporary songs
                 if song.temporary:
@@ -347,8 +352,8 @@ class SongMediaItem(MediaManagerItem):
         """
         log.debug('display results Themes')
         self.list_view.clear()
-        search_results.sort(key=lambda song: (get_natural_key(song.theme_name),
-                            song.sort_key))
+        get_theme_key = lambda song: (get_natural_key(song.theme_name), song.sort_key)
+        search_results.sort(key=get_theme_key)
         for song in search_results:
             # Do not display temporary songs
             if song.temporary:
@@ -367,8 +372,8 @@ class SongMediaItem(MediaManagerItem):
         """
         log.debug('display results CCLI number')
         self.list_view.clear()
-        search_results.sort(key=lambda song: (get_natural_key(song.ccli_number),
-                            song.sort_key))
+        get_cclinumber_key = lambda song: (get_natural_key(song.ccli_number), song.sort_key)
+        search_results.sort(key=get_cclinumber_key)
         for song in search_results:
             # Do not display temporary songs
             if song.temporary: