diff --git a/hr_shift/models/shift_planning.py b/hr_shift/models/shift_planning.py
index 5aad849..c0cbdc5 100644
--- a/hr_shift/models/shift_planning.py
+++ b/hr_shift/models/shift_planning.py
@@ -59,7 +59,12 @@ def default_get(self, fields_list):
         # Get the last plan and start from there
         result = super().default_get(fields_list)
         last_plan = self._get_last_plan()
-        if not last_plan or result.get("year") or result.get("week_number"):
+        if (
+            not last_plan
+            or not last_plan.end_date
+            or result.get("year")
+            or result.get("week_number")
+        ):
             return result
         year, week_number, *_ = (
             last_plan.end_date + relativedelta(days=1)
@@ -277,7 +282,7 @@ def _generate_shift_lines(self):
                 )
             shift.line_ids.create(shift_lines)
 
-    def create(Self, vals_list):
+    def create(self, vals_list):
         res = super().create(vals_list)
         res._generate_shift_lines()
         return res
diff --git a/hr_shift/wizards/shift_planning_wizard.py b/hr_shift/wizards/shift_planning_wizard.py
index f12fee4..db031a0 100644
--- a/hr_shift/wizards/shift_planning_wizard.py
+++ b/hr_shift/wizards/shift_planning_wizard.py
@@ -43,8 +43,8 @@ def default_get(self, fields_list):
         result = super().default_get(fields_list)
         default_vals = self.env["hr.shift.planning"].default_get([])
         result.update(
-            week_number=default_vals["week_number"],
-            year=default_vals["year"],
+            week_number=default_vals.get("week_number"),
+            year=default_vals.get("year"),
         )
         if not result.get("from_planning_id"):
             result.update(