php $key = sanitize_text_field( $key ); if ( preg_match('/^[a-zA-Z0-9_]*$/', $key) ) { return $key; } else { return ''; } php if ( preg_match('/^[a-z]{2}_[A-Z]{2}$/', $locale ) ) { return $locale; } else { return 'en_US'; } php $apikey = '&apikey=' . esc_html( $apikey ) . '&ver=2.1'; $apikey_param = $apikey !== '' ? '&apikey=' . rawurlencode( urldecode($apikey ) : '';