How to show SKU in custom template? Please help

I need to include the product SKU in the custom template. I see that in “Template” there are some checks to include SKU and other fields in the template by default, but when I use a custom template and mark all the fields, the SKU field does not appear.

Following the instructions in the FAQ I tried adding this code:

echo BEWPI()->templater()->get_meta( '_sku' );

here:

foreach ( $row as $column_key => $data ) {
$templater->display_data_recursive( $column_key, $data );
}
// Show SKU
echo ''; echo BEWPI()->templater()->get_meta( '_sku' ); echo '';

echo '';
}

But it must not be correct and it breaks the generation of the invoice.

I’ve been looking through the rest of the related questions but haven’t found any useful answers.

Please can you help me? I have looked everywhere for this information and there is no way it will work.

The page I need help with: [log in to see the link]