+http://stackoverflow.com/questions/14201210/impossible-to-initialize-elixir
+
+--- Elixir-0.7.1/elixir/entity.py~ 2009-11-13 21:50:38.000000000 +0200
++++ Elixir-0.7.1/elixir/entity.py 2015-02-11 21:04:09.963209077 +0200
+@@ -15,8 +15,9 @@
+ from sqlalchemy import Table, Column, Integer, desc, ForeignKey, and_, \
+ ForeignKeyConstraint
+ from sqlalchemy.orm import MapperExtension, mapper, object_session, \
+- EXT_CONTINUE, polymorphic_union, ScopedSession, \
++ EXT_CONTINUE, polymorphic_union, \
+ ColumnProperty
++from sqlalchemy.orm import scoped_session as ScopedSession
+ from sqlalchemy.sql import ColumnCollection
+
+ import elixir