public function addForm(FormObject $form)
    {
        if (true === $this->hasForm($form->getClassName(), $form->getName())) {
            throw DuplicateEntryException::formWasAlreadyRegistered($form);
        }

        $form->getConfiguration()->setParents([$this]);

        $this->forms[$form->getClassName()][$form->getName()] = $form;
    }