After update i get this error on login page , any help pls

Traceback (most recent call last):
File “/home/frappe/frappe-bench/apps/frappe/frappe/app.py”, line 58, in application
init_request(request)
File “/home/frappe/frappe-bench/apps/frappe/frappe/app.py”, line 120, in init_request
frappe.local.http_request = frappe.auth.HTTPRequest()
File “/home/frappe/frappe-bench/apps/frappe/frappe/auth.py”, line 51, in init
frappe.local.login_manager = LoginManager()
File “/home/frappe/frappe-bench/apps/frappe/frappe/auth.py”, line 113, in init
self.make_session(resume=True)
File “/home/frappe/frappe-bench/apps/frappe/frappe/auth.py”, line 182, in make_session
full_name=self.full_name, user_type=self.user_type)
File “/home/frappe/frappe-bench/apps/frappe/frappe/sessions.py”, line 196, in init
self.resume()
File “/home/frappe/frappe-bench/apps/frappe/frappe/sessions.py”, line 251, in resume
data = self.get_session_record()
File “/home/frappe/frappe-bench/apps/frappe/frappe/sessions.py”, line 268, in get_session_record
r = self.get_session_data()
File “/home/frappe/frappe-bench/apps/frappe/frappe/sessions.py”, line 284, in get_session_data
data = self.get_session_data_from_db()
File “/home/frappe/frappe-bench/apps/frappe/frappe/sessions.py”, line 311, in get_session_data_from_db
get_expiry_period(self.device)))
File “/home/frappe/frappe-bench/apps/frappe/frappe/sessions.py”, line 381, in get_expiry_period
exp_sec = frappe.defaults.get_global_default(key) or default
File “/home/frappe/frappe-bench/apps/frappe/frappe/defaults.py”, line 105, in get_global_default
if not_in_user_permission(key, value):
File “/home/frappe/frappe-bench/apps/frappe/frappe/defaults.py”, line 61, in not_in_user_permission
user_permission = get_user_permissions(user).get(frappe.unscrub(key)) or []
File “/home/frappe/frappe-bench/apps/frappe/frappe/defaults.py”, line 74, in get_user_permissions
return _get_user_permissions(user)
File “/home/frappe/frappe-bench/apps/frappe/frappe/core/doctype/user_permission/user_permission.py”, line 73, in get_user_permissions
decendants = frappe.db.get_descendants(perm.allow, perm.for_value)
File “/home/frappe/frappe-bench/apps/frappe/frappe/database.py”, line 970, in get_descendants
lft, rgt = self.get_value(doctype, name, (‘lft’, ‘rgt’))
TypeError: ‘NoneType’ object is not iterable