How to use the ta.forms.TAApplicationForm function in ta

skill_values = []
        for s in skills:
            try:
                val = SkillLevel.objects.get(app=application, skill=s).level
            except SkillLevel.DoesNotExist:
                val = 'WIL'
            if val not in LEVELS:
                val = 'NONE'
            skill_values.append((s.position, s.name, val))
    else:
        # new application
        search_form = StudentSearchForm()
        courses_formset = CoursesFormSet()
        for f in courses_formset:
            f.fields['course'].choices = course_choices
        ta_form = TAApplicationForm(prefix='ta', initial={'sin': sin})
        ta_form.add_extra_questions(posting)
        campus_preferences = [(lbl, name, 'WIL') for lbl,name in CAMPUS_CHOICES if lbl in used_campuses]
        skill_values = [(s.position, s.name, 'NONE') for s in skills]
        today = datetime.date.today()
        if(posting.closes < today):
            messages.warning(request, "The closing date for this posting has passed.  Your application will be marked 'late' and may not be considered.")

    context = {
                    'posting':posting,
                    'manual':manual,
                    'editing': editing,
                    'ta_form':ta_form,
                    'search_form':search_form,
                    'courses_formset':courses_formset,
                    'campus_preferences':campus_preferences,
                    'campus_pref_choices':PREFERENCE_CHOICES,

for c in used_campuses:
            val = request.POST.get('campus-'+c, None)
            if val not in PREFERENCES:
                val = 'WIL'
            campus_preferences.append((c, CAMPUSES[c], val))
        skill_values = []
        for s in skills:
            val = request.POST.get('skill-'+str(s.position), None)
            if val not in LEVELS:
                val = 'NONE'
            skill_values.append((s.position, s.name, val))

    elif editing:
        # editing: build initial form from existing values
        
        ta_form = TAApplicationForm(prefix='ta', instance=application)
        # Stupidly, the filefields don't consider themselves "filled" if we have a previous instance that contained
        # the right fields anyway.  Manually check and clear the required part.
        if application.resume:
            ta_form.fields['resume'].required = False
        if application.transcript:
            ta_form.fields['transcript'].required = False
        ta_form.add_extra_questions(posting)
        cp_init = [{'course': cp.course, 'taken': cp.taken, 'exper':cp.exper} for cp in old_coursepref]
        search_form = None
        courses_formset = CoursesFormSet(initial=cp_init)
        for f in courses_formset:
            f.fields['course'].choices = course_choices

        # build values for template with entered values
        campus_preferences = []
        for c in used_campuses:

if manual:
            try:
                person = get_object_or_404(Person, emplid=int(request.POST['search']))
            except ValueError:
                search_form = StudentSearchForm(request.POST['search'])
                messages.error(request, "Invalid emplid %s for person." % (request.POST['search']))
                return HttpResponseRedirect(reverse('ta:new_application_manual', args=(post_slug,)))
            
            #Check to see if an application already exists for the person 
            existing_app = TAApplication.objects.filter(person=person, posting=posting)
            if existing_app.count() > 0: 
                messages.success(request, "%s has already applied for the %s %s posting." % (person, posting.unit, posting.semester))
                return HttpResponseRedirect(reverse('ta:view_application', kwargs={'post_slug': existing_app[0].posting.slug, 'userid': existing_app[0].person.userid}))
        
        if editing:
            ta_form = TAApplicationForm(request.POST, request.FILES, prefix='ta', instance=application)
        else:
            ta_form = TAApplicationForm(request.POST, request.FILES, prefix='ta')

        ta_form.add_extra_questions(posting)

        courses_formset = CoursesFormSet(request.POST)
        for f in courses_formset:
            f.fields['course'].choices = course_choices

        if ta_form.is_valid() and courses_formset.is_valid():
            # No duplicates allowed
            courses = []
            for (rank,form) in enumerate(courses_formset):
                if 'course' in form.cleaned_data and form.cleaned_data['course']:
                    courses.append( form.cleaned_data['course'] )

person = get_object_or_404(Person, emplid=int(request.POST['search']))
            except ValueError:
                search_form = StudentSearchForm(request.POST['search'])
                messages.error(request, "Invalid emplid %s for person." % (request.POST['search']))
                return HttpResponseRedirect(reverse('ta:new_application_manual', args=(post_slug,)))
            
            #Check to see if an application already exists for the person 
            existing_app = TAApplication.objects.filter(person=person, posting=posting)
            if existing_app.count() > 0: 
                messages.success(request, "%s has already applied for the %s %s posting." % (person, posting.unit, posting.semester))
                return HttpResponseRedirect(reverse('ta:view_application', kwargs={'post_slug': existing_app[0].posting.slug, 'userid': existing_app[0].person.userid}))
        
        if editing:
            ta_form = TAApplicationForm(request.POST, request.FILES, prefix='ta', instance=application)
        else:
            ta_form = TAApplicationForm(request.POST, request.FILES, prefix='ta')

        ta_form.add_extra_questions(posting)

        courses_formset = CoursesFormSet(request.POST)
        for f in courses_formset:
            f.fields['course'].choices = course_choices

        if ta_form.is_valid() and courses_formset.is_valid():
            # No duplicates allowed
            courses = []
            for (rank,form) in enumerate(courses_formset):
                if 'course' in form.cleaned_data and form.cleaned_data['course']:
                    courses.append( form.cleaned_data['course'] )

            if len(courses) != len(set(courses)):
                messages.error(request, "You have selected duplicate courses. Please select 5 different courses. ")

def __init__(self, *args, **kwargs):
        super(TAApplicationForm, self).__init__(*args, **kwargs)
        self.fields['sin'].help_text = 'Social insurance number (required for receiving payments: if you don\'t have a SIN yet, please enter "000000000".)'
        self.fields['sin'].required = True
        self.fields['current_program'].required = True
        self.fields['resume'].required = True
        self.fields['transcript'].required = True