I have a project that's a few years old, but needs some maintenance. Since I last worked on the project, two major things have happened. First, Elixir -- a declarative layer on top of SQLAlchemy -- has not been maintained. Secondly, SQLAlchemy now has its own declarative layer.
Rather than continue using Elixir, I decided to migrate my data models to use the new SQLAlchemy declarative layer, which interestingly enough appear to be relatively compatible with Elixir's philosophy.
The first thing I did was do a direct mapping in my model columns and update the import statements.
# from Elixir import Entity, Field, DateTime, Unicode, Integer, Boolean, setup_all, create_all, session, metadata
from sqlalchemy import Column, DateTime, String, Integer, ForeignKey, Boolean
from sqlalchemy.ext.declarative import declarative_base