Smile\ElasticsuiteThesaurus\Block\Adminhtml\Thesaurus\Create\Form::_prepareForm PHP Method

    protected function _prepareForm()
    {
        /** @var \Magento\Framework\Data\Form $form */
        $form = $this->_formFactory->create(['data' => ['id' => 'edit_form', 'action' => $this->getData('action')]]);
        $thesaurusTypes = [['value' => ThesaurusInterface::TYPE_SYNONYM, 'label' => __('Synonym')], ['value' => ThesaurusInterface::TYPE_EXPANSION, 'label' => __('Expansion')]];
        $fieldset = $form->addFieldset('base_fieldset', ['legend' => __('Type')]);
        $fieldset->addField('type', 'select', ['name' => 'type', 'label' => __('Thesarurus Type'), 'title' => __('Thesarurus Type'), 'values' => $thesaurusTypes]);
        $form->setUseContainer(true);
        $this->setForm($form);
        return parent::_prepareForm();
    }