mrjoes/flask-admin — pull request #60 by borisnieuwenhuis (2012-09-13 11:29:17+00:00)
Title: fix bug in form.py wen checking callable_default

raise TypeError("Boolean value of this clause is not defined")
TypeError: Boolean value of this clause is not defined

see
http://www.sqlalchemy.org/trac/wiki/06Migration#AnImportantExpressionLanguageGotcha