Django:What is wrong with my code?
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These are my models:

    class war(models.Model):
    	title = models.CharField(max_length=20)
    
    class option(models.Model):
    	warval =models.ForeignKey(war)
    	value = models.CharField(max_length=10)
    
    class warform(ModelForm):
    	class Meta:
    		model = war
    		
    class option_form(ModelForm):
    	class Meta:
    		model = option
		exclude = ('warval')

And this is the view which handles creation of option:

    def warhandler(request,war_id):
    	f=modelformset_factory(option,form=option_form)
    	wobj=get_object_or_404(war,pk=war_id)
    	if request.method == 'POST':
    		formset = f(request.POST,queryset=option.objects.filter(warval=wobj))
    		if formset.is_valid():
    			formset.save()
    			return HttpResponse("Saved!check your model")	
    		else:
    			return render_to_response("formset.html",RequestContext(request,{"set":formset}))
    	else:
    		formset = f(queryset=option.objects.filter(warval=wobj))
    		print(formset)
    		return render_to_response("formset.html",RequestContext(request,{"set":formset,"war":wobj}))

So when I submit the form to this view,I get the following error:

    Exception Type:	IntegrityError
    Exception Value: shit_option.warval_id may not be NULL

I know what this error is and why it is coming but how can I remove this error? 