Traceback (most recent call last):
  File "C:\data\odoo\odoo\fields.py", line 940, in __get__
    value = record.env.cache.get(record, self)
  File "C:\data\odoo\odoo\api.py", line 967, in get
    value = self._data[key][field][record._ids[0]]
KeyError: <odoo.models.NewId object at 0x000002005B6709A8>

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\data\odoo\odoo\http.py", line 651, in _handle_exception
    return super(JsonRequest, self)._handle_exception(exception)
  File "C:\data\odoo\odoo\http.py", line 310, in _handle_exception
    raise pycompat.reraise(type(exception), exception, sys.exc_info()[2])
  File "C:\data\odoo\odoo\tools\pycompat.py", line 87, in reraise
    raise value
  File "C:\data\odoo\odoo\http.py", line 693, in dispatch
    result = self._call_function(**self.params)
  File "C:\data\odoo\odoo\http.py", line 342, in _call_function
    return checked_call(self.db, *args, **kwargs)
  File "C:\data\odoo\odoo\service\model.py", line 97, in wrapper
    return f(dbname, *args, **kwargs)
  File "C:\data\odoo\odoo\http.py", line 335, in checked_call
    result = self.endpoint(*a, **kw)
  File "C:\data\odoo\odoo\http.py", line 937, in __call__
    return self.method(*args, **kw)
  File "C:\data\odoo\odoo\http.py", line 515, in response_wrap
    response = f(*args, **kw)
  File "c:\data\odoo\addons\web\controllers\main.py", line 934, in call_kw
    return self._call_kw(model, method, args, kwargs)
  File "c:\data\odoo\addons\web\controllers\main.py", line 926, in _call_kw
    return call_kw(request.env[model], method, args, kwargs)
  File "C:\data\odoo\odoo\api.py", line 689, in call_kw
    return call_kw_multi(method, model, args, kwargs)
  File "C:\data\odoo\odoo\api.py", line 680, in call_kw_multi
    result = method(recs, *args, **kwargs)
  File "C:\data\odoo\odoo\models.py", line 5198, in onchange
    snapshot1 = Snapshot(record, nametree)
  File "C:\data\odoo\odoo\models.py", line 5105, in __init__
    if subnames else record[name]
  File "C:\data\odoo\odoo\models.py", line 4785, in __getitem__
    return self._fields[key].__get__(self, type(self))
  File "C:\data\odoo\odoo\fields.py", line 946, in __get__
    self.determine_draft_value(record)
  File "C:\data\odoo\odoo\fields.py", line 1066, in determine_draft_value
    self._compute_value(record)
  File "C:\data\odoo\odoo\fields.py", line 1002, in _compute_value
    getattr(records, self.compute)()
  File "c:\data\addon\custom-addons\fleet_tire_management\models\tire_management.py", line 153, in _compute_cek_days
    date_2 = datetime.datetime.strptime(r.issue_date, '%Y-%m-%d')
TypeError: strptime() argument 1 must be str, not bool

my method.py

cek_days = fields.Integer(string='Hari cek - Hari pasang' , compute='_compute_cek_days')
issue_date = fields.Date(string="Tanggal Pemasangan")
cek_date = fields.Date(string='Tanggal Pengecekan / Penggantian')

@api.depends('cek_date','issue_date')
    def _compute_cek_days(self):
        for r in self:
            # r.cek_days = r.cek_date - r.issue_date
            date_1 = datetime.datetime.strptime(r.cek_date, '%Y-%m-%d')
            date_2 = datetime.datetime.strptime(r.issue_date, '%Y-%m-%d')

            cek_hasil = date_1 - date_2
            cek_day = re.sub('[^0-9]', '', str(cek_hasil))
            r.cek_days = (int(cek_day))# / 100000

xml