[entity] do not raise an AssertionError if the kwargs given to set_relations/attributes is empty Regression was introduced in 3.16 with the new cw_set API. Old set_relations and set_attributes methods did not crash on empty kwargs. Closes #3104019.

# -*- coding: utf-8 -*-
# copyright %(year)s %(author)s, all rights reserved.
# contact %(author-web-site)s -- mailto:%(author-email)s
#
%(long-license)s
"""%(distname)s schema"""