[rset] New method: ResultSet.one() This method will return exactly one entity while enforcing its existence and unicity. The idea is shamelessly borowed from SQLAlchemy Query.one(). Closes #3352314 [jcr: use len(self) instead of len(self.rows)]

include *.py
include */*.py
recursive-include data *.gif *.png *.ico *.css *.js
recursive-include i18n *.po
recursive-include wdoc *