change offset from float to decimal

AKModel/models.py

@@ -3,6 +3,7 @@ import json
 import math
 from dataclasses import dataclass
 from datetime import datetime, timedelta
+from decimal import Decimal
 from typing import Iterable, Generator
 
 from django.db import models
@@ -935,7 +936,7 @@ class AKSlot(models.Model):
                 return []
             return [f"availability-person-{owner.pk}"]
 
-        ceil_offet_eps = 1e-4
+        ceil_offet_eps = decimal.Decimal(1e-4)
 
         # self.slots_in_an_hour is set in AKJSONExportView
         data = {