Generating huge debug

This plugin is generating a lot of PHP Notices due to one line in the code… is there any way to fix this? I am getting dozens of PHP Notices logged into my debug.log from this plugin, and all of the Notices say:

PHP Notice: Undefined index: hiddenblock in /path/to/install/wp-content/plugins/hide-block/hide-block.php on line 73

Which looks like it’s referring to the part in your plugin’s code which reads:

// Dynamic Return Contents
function hideblock_plugin_frontend( $block_content, $block ) {
	if( $block['attrs']['hiddenblock'] ) {
		return null;
	} else {
		return $block_content;
	}
}
add_filter( 'render_block', 'hideblock_plugin_frontend', 10, 3);

What can be modified about the code to resolve this and stop the Notices?
Thanks!