filtering the dates within the project's duration

Using Django Forms & APIs
1

there’s something wrong within my code, because the end_date validation don’t work, but the other’s are working,

I just want to have a validation error if a user pick a date that not within the project’s duration

here is my models.py:

class Project(models.Model):  # WORKING
	class Status(models.TextChoices):
		On_Hold = "On Hold", "On Hold"
		Ongoing = "Ongoing", "Ongoing"
		Cancelled = "Cancelled", "Cancelled"
		Completed = "Completed", "Completed"

	name = models.CharField(_("Project's Name"), max_length=250)
	address = models.CharField(_("Project Location"), max_length=250)
	budget = models.DecimalField(_("Budget"), max_digits=10, decimal_places=2, default=0)
	status = models.CharField(max_length=50, choices=Status.choices, default=Status.On_Hold)
	owner = models.ForeignKey(Client, on_delete=models.SET_NULL, related_name="projects", null=True, blank=True)
	# Projects Duration
	start_date = models.DateField(null=True, blank=True)
	end_date = models.DateField(null=True, blank=True)
	duration = models.CharField(max_length=3, blank=True)

class Boq(models.Model):
	project = models.ForeignKey(Project, on_delete=models.SET_NULL, null=True, blank=True)
	description = models.CharField(max_length=250, null=True, blank=True)
	quantity = models.DecimalField(max_digits=10, decimal_places=2, default=1)
	unit = models.CharField(max_length=10, choices=Units.choices, default=Units.LOT)
	rate_material = models.DecimalField(_("Unit Cost for Material"), max_digits=10, decimal_places=2, default=0)
	material_cost = models.DecimalField(_("Material Cost"), max_digits=10, decimal_places=2, default=0)
	rate_labor = models.DecimalField(_("Unit Cost for Labor"), max_digits=10, decimal_places=2, default=0)
	labor_cost = models.DecimalField(_("Labor Cost"), max_digits=10, decimal_places=2, default=0)
	line_total = models.DecimalField(_("Line Total"), max_digits=10, decimal_places=2, default=0)
	
	# Task Duration (item, description = task)
	start_date = models.DateField(null=True, blank=True)
	end_date = models.DateField(null=True, blank=True)
	duration = models.CharField(max_length=3, blank=True)

forms.py

class BoqForm(forms.ModelForm):
	start_date = forms.DateField(required=False, widget=forms.DateInput(attrs={'type': 'date'}))
	end_date = forms.DateField(required=False, widget=forms.DateInput(attrs={'type': 'date'}))
	
	class Meta:
		model = Boq
		fields = ['item', 'description', 'quantity', 'unit', 'rate_material', 'rate_labor', 'start_date', 'end_date']
	
	def clean(self):
		cleaned_data = super().clean()
		start_date = cleaned_data.get('start_date')
		end_date = cleaned_data.get('end_date')
		today = date.today()
		project = self.instance.project
		
		# Check if start_date and end_date are within the project's duration
		if project is not None and start_date and project.start_date and start_date < project.start_date:
			print("Start date cannot be earlier than the project's start date.")
			raise forms.ValidationError("Start date cannot be earlier than the project's start date.")

		elif project is not None and end_date and project.end_date and end_date > project.end_date:
			print("End date cannot exceed the project's end date.")
			raise forms.ValidationError("End date cannot exceed the project's end date.")
		if start_date and end_date and start_date >= end_date:
			print("Selected dates are incorrect, please select again.")
			raise forms.ValidationError("Selected dates are incorrect, please select again.")
		
		if start_date and start_date < today:
			print("Start date cannot be in the past.")
			raise forms.ValidationError("Start date cannot be in the past.")
		
		if end_date and end_date < today:
			print("End date cannot be in the past.")
			raise forms.ValidationError("End date cannot be in the past.")
		
		return cleaned_data

views.py:

def add_project_boq(request, pk):
    project = get_object_or_404(Project, pk=pk)

    if request.method == 'POST':
        form = BoqForm(request.POST)
        if form.is_valid():
            boq = form.save(commit=False)
            boq.project = project
            boq.save()
            project.boq_set.add(boq)
            form = BoqForm()
    else:
        form = BoqForm()

    boqs = project.boq_set.all()
    context = {'boqs': boqs, 'form': form}
    return render(request, 'pms/boq/boq-list-copy.html', context)