public function render_customer_revenue_column($id)
 {
     $customer = Customer::get($id);
     $revenue = 0.0;
     $stats = get_post_meta($customer->get_ID(), '_easy_customer_invoices_stats', true);
     if (is_array($stats) && isset($stats['total'])) {
         $revenue = $stats['total'];
     }
     echo Util::format_price($revenue);
 }
 public function get_customer()
 {
     return Customer::get($this->get_meta('customer'));
 }
 public function get_customer_schema()
 {
     return Entities\Customer::get_api_schema();
 }