<?php // don't add this line since it's already in your functions.php file


function _add_label_si_stripe_js_data_attributes( $data_atts = array() ) {
	$data_atts['data-label'] = 'Betalen met een kaart';
	return $data_atts;
}
add_filter( 'si_stripe_js_data_attributes', '_add_label_si_stripe_js_data_attributes' );