Additional None-ness check.

src/caosadvancedtools/cfood.py

@@ -855,6 +855,9 @@ class CMeal():
     def all_groups_equal(cls, m1, m2):
         equal = True
 
+        if m2 is None:
+            return False
+
         for group in cls.matching_groups:
             if (group not in m1.groupdict() or
                     group not in m2.groupdict() or