-

cool-RR · cool-RR · commit c08b07974075 · 2014-10-20T17:59:28.000+03:00
diff --git a/source_py2/python_toolbox/combi/perming/perm_space.py b/source_py2/python_toolbox/combi/perming/perm_space.py
@@ -59,7 +59,7 @@ def __call__(cls, *args, **kwargs):
         
 class PermSpace(_VariationRemovingMixin, _VariationAddingMixin,
                 _FixedMapManagingMixin, sequence_tools.CuteSequenceMixin,
-                collections.Sequence, metaclass=PermSpaceType):
+                collections.Sequence):
     '''
     A space of permutations on a sequence.
     
@@ -149,6 +149,8 @@ class PermSpace(_VariationRemovingMixin, _VariationAddingMixin,
     A perm space that has none of these variations is called pure.
     '''
     
+    __metaclass__ = PermSpaceType
+    
     @classmethod
     def coerce(cls, argument):
         '''Make `argument` into something of class `cls` if it isn't.'''
@@ -917,6 +919,7 @@ def short_length_string(self):
             return str(self.length)
     
     __bool__ = lambda self: bool(self.length)
+    __nonzero__ = __bool__
     
     _domain_set = caching.CachedProperty(
         lambda self: set(self.domain),
diff --git a/source_py2/python_toolbox/combi/perming/variations.py b/source_py2/python_toolbox/combi/perming/variations.py
@@ -116,7 +116,7 @@ class VariationSelectionType(type):
     __call__ = lambda cls, variations: cls._create_from_sorted_set(
                                         sortedcontainers.SortedSet(variations))
     
-class VariationSelection(metaclass=VariationSelectionType):
+class VariationSelection(object):
     '''
     A selection of variations of a `PermSpace`.
     
@@ -132,6 +132,9 @@ class VariationSelection(metaclass=VariationSelectionType):
     with the same variations, you'll get the original `VariationSelection`
     object you created.
     '''
+    
+    __metaclass__ = VariationSelectionType
+    
     @classmethod
     @caching.cache()
     def _create_from_sorted_set(cls, variations):
