Create branch 16.0

--HG-- branch : 16.0

models/account_period.py

@@ -17,9 +17,6 @@
 #    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
 ##############################################################################
-import datetime
-from typing import Optional
-
 from odoo import api, fields, models
 
 
@@ -86,4 +83,4 @@
 
         self.ensure_one()
 
-        self.state = "draft"
\ No newline at end of file
+        self.state = "draft"