docs: def add_view(self, request, form_url='', extra_context=None):
          "The 'add' admin view for this model."
          model = self.model
          opts = model._meta
  
          if not self.has_add_permission(request):
              raise PermissionDenied
  
          ModelForm = self.get_form(request)
          formsets = []
          inline_instances = self.get_inline_instances(request, None)
          if request.method == 'POST':
              form = ModelForm(request.POST, request.FILES)
              if form.is_valid():
                  new_object = self.save_form(request, form, change=False)
                  form_validated = True
              else:
                  form_validated = False
                  new_object = self.model()
              prefixes = {}
              for FormSet, inline in self.get_formsets_with_inlines(request):
                  prefix = FormSet.get_default_prefix()
                  prefixes[prefix] = prefixes.get(prefix, 0) + 1
                  if prefixes[prefix] != 1 or not prefix:
                      prefix = "%s-%s" % (prefix, prefixes[prefix])
                  formset = FormSet(data=request.POST, files=request.FILES,
                      instance=new_object,
                      save_as_new="_saveasnew" in request.POST,
                      prefix=prefix, queryset=inline.get_queryset(request))
                  formsets.append(formset)
                  if inline.inlines:
                      self.add_nested_inline_formsets(request, inline, formset)
              if self.all_valid_with_nesting(formsets) and form_validated:
                  self.save_model(request, new_object, form, False)
                  self.save_related(request, form, formsets, False)
                  args = ()
                  # Provide `add_message` argument to ModelAdmin.log_addition for
                  # Django 1.9 and up.
                  if VERSION[:2] >= (1, 9):
                      add_message = self.construct_change_message(
                          request, form, formsets, add=True
                      )
                      args = (request, new_object, add_message)
                  else:
                      args = (request, new_object)
                  self.log_addition(*args)
                  return self.response_add(request, new_object)
          else:
              # Prepare the dict of initial data from the request.
              # We have to special-case M2Ms as a list of comma-separated PKs.
              initial = dict(request.GET.items())
              for k in initial:
                  try:
                      f = opts.get_field(k)
                  except models.FieldDoesNotExist:
                      continue
                  if isinstance(f, models.ManyToManyField):
                      initial[k] = initial[k].split(",")
              form = ModelForm(initial=initial)
              prefixes = {}
              for FormSet, inline in self.get_formsets_with_inlines(request):
                  prefix = FormSet.get_default_prefix()
                  prefixes[prefix] = prefixes.get(prefix, 0) + 1
                  if prefixes[prefix] != 1 or not prefix:
                      prefix = "%s-%s" % (prefix, prefixes[prefix])
                  formset = FormSet(instance=self.model(), prefix=prefix,
                      queryset=inline.get_queryset(request))
                  formsets.append(formset)
                  if hasattr(inline, 'inlines') and inline.inlines:
                      self.add_nested_inline_formsets(request, inline, formset)
  
          adminForm = helpers.AdminForm(form, list(self.get_fieldsets(request)),
              self.get_prepopulated_fields(request),
              self.get_readonly_fields(request),
              model_admin=self)
          media = self.media + adminForm.media
  
          inline_admin_formsets = []
          for inline, formset in zip(inline_instances, formsets):
              fieldsets = list(inline.get_fieldsets(request))
              readonly = list(inline.get_readonly_fields(request))
              prepopulated = dict(inline.get_prepopulated_fields(request))
              inline_admin_formset = helpers.InlineAdminFormSet(inline, formset,
                  fieldsets, prepopulated, readonly, model_admin=self)
              inline_admin_formsets.append(inline_admin_formset)
              media = media + inline_admin_formset.media
              if hasattr(inline, 'inlines') and inline.inlines:
                  media += self.wrap_nested_inline_formsets(request, inline, formset)
  
          context = {
              'title': _('Add %s') % force_text(opts.verbose_name),
              'adminform': adminForm,
              'is_popup': "_popup" in request.GET,
              'show_delete': False,
              'media': media,
              'inline_admin_formsets': inline_admin_formsets,
              'errors': helpers.AdminErrorList(form, formsets),
              'app_label': opts.app_label,
              }
          context.update(self.admin_site.each_context(request))
          context.update(extra_context or {})
          return self.render_change_form(request, context, form_url=form_url, add=True)