error datefiled input when add new record - django

Question

I have next problem.
I have models: Period and CompletedWork
class Period(models.Model):
date = models.DateField()
def __repr__(self):
return self.date
class CompletedWork(models.Model):
period = models.ForeignKey(directory.Period,
on_delete=models.SET('deleted date'),
)
worker = models.ForeignKey(
settings.AUTH_USER_MODEL,
on_delete=models.SET('deleted worker'),
related_name='worker_do', default=settings.AUTH_USER_MODEL
)
work_done = models.ForeignKey(directory.WorksType, on_delete=models.SET('deleted works type'))
work_scope = models.FloatField(blank=True, null=True)
work_notes = models.CharField(_("Comments"), max_length=70, blank=True, null=True, )
record_author = models.ForeignKey(
settings.AUTH_USER_MODEL,
on_delete=models.SET('deleted user'),
related_name='record_author', auto_created=True,
)
record_date = models.DateTimeField(auto_now=True)
checked_by_head = models.BooleanField(default=False)
active = models.BooleanField(default=True)
def __repr__(self):
return f'{self.period}, {self.worker}, {self.work_done}'
def __str__(self):
return self.__repr__()
def is_active(self):
if self.active:
return True
return False
def __str__(self):
return str(self.__repr__())
In the forms I make a widget for Date input:
class CompletedWorkForm(forms.ModelForm):
class Meta:
model = CompletedWork
fields = (
'period',
'worker',
'work_done',
'work_scope',
'work_notes',
)
widgets = {
'period': DatePickerInput(),
}
widget.py looks like this:
class DatePickerInput(forms.DateInput):
input_type = 'date'
my view:
class CreateCompletedWorkView(LoginRequiredMixin, SuccessMessageMixin, CreateView):
model = CompletedWork
form_class = CompletedWorkForm
template_name = 'completed_work_add.html'
success_url = reverse_lazy('completed_work_list')
success_message = f'Record successfully added'
def get_form_kwargs(self):
kwargs = super(CreateCompletedWorkView, self).get_form_kwargs()
kwargs['user'] = self.request.user
return kwargs
def form_valid(self, form):
form.instance.record_author = self.request.user
return super().form_valid(form)
And now I have a problem creating a new record:
"Select a valid choice. That choice is not one of the available choices."
Please tell me how can I fixed. I understand, that maybe problem with the format that I get after POST