Electro - Sale label only for logged in users

function.php

function electro_get_sale_flash( $html, $post, $product ) {
  if( is_user_logged_in() ) {
   $html = '<span class="onsale">-' . electro_get_savings_on_sale( $product, 'percentage' ) . '</span>';

        return apply_filters( 'electro_get_sale_flash', $html, $post, $product );
    }
   }