<page xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:View/Layout/etc/page_configuration.xsd">
        <reference name="content">
            <block class="Slimcd\Payment\Block\Adminhtml\Index" name="custom_index"/>
        </reference>
</page>