Fix WeekDaysType support for py33

sqlalchemy_utils/types/bit.py

@@ -16,5 +16,7 @@ class BitType(sa.types.TypeDecorator):
         # Use the native BIT type for drivers that has it.
         if dialect.name == 'postgresql':
             return dialect.type_descriptor(BIT(self.length))
+        elif dialect.name == 'sqlite':
+            return dialect.type_descriptor(sa.String(self.length))
         else:
             return dialect.type_descriptor(type(self.impl)(self.length))

sqlalchemy_utils/types/weekdays.py

@@ -48,6 +48,10 @@ class WeekDaysType(types.TypeDecorator, ScalarCoercible):
 
     impl = BitType(WeekDay.NUM_WEEK_DAYS)
 
+    @property
+    def comparator_factory(self):
+        return self.impl.comparator_factory
+
     def process_bind_param(self, value, dialect):
         if isinstance(value, WeekDays):
             return value.as_bit_string()