Workaround
@token.setter
def token(self, value):
self._client.token = value
#self._client.populate_token_attributes(value) <----- Remarked this line 114 in /home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/requests_oauthlib/oauth2_session.py
Not sure what else to do but had to do this to continue creating new sites. If somebody has insights on this it will be useful to know the consequences.