[repo creation] removing existing entities of 'single' cardinality relatino should be considered as 'activeintegrity' hook. Also don't disable that category during repo creation to avoid pb such as two default workflows for one entity types
"""pre 3.6 bw compat"""
# pylint: disable-msg=W0614,W0401
from warnings import warn
warn('moved to cubicweb.mixins', DeprecationWarning, stacklevel=2)
from cubicweb.mixins import *