MAINT: do only call update on the container when there is content

src/caosadvancedtools/cfood.py

@@ -118,6 +118,9 @@ class AbstractCFood(object):
         """ Updates the self.to_be_updated Container, i.e. pushes the changes
         to CaosDB
         """
+
+        if len(self.to_be_updated) == 0:
+            return
         get_ids_for_entities_with_names(self.to_be_updated)
         self.to_be_updated.update()