does SQLAlchemy have something similar to Django\'s signal concept? Basically, I\'d like to trigger a few functions when I pre-save or post-save some entity objects. Thanks.
You didn't make clear, whether you are integrating SQLAlchemy and Django, or you JUST want equivalent of django-signals in SQLAlchemy.
If you want equivalent of Django signals like post_save, pre_save, pre_delete etc, i would refer you the page,
sqlalchemy.orm.interfaces.MapperExtension