get_transient_prefix() public method

Returns the dirname of the slug and limits it to 15 chars
public get_transient_prefix ( ) : string
return string
 /**
  * Constructor
  *
  * @param string $api_url     The url to the EDD shop
  * @param string $item_name   The item name in the EDD shop
  * @param string $license_key The (valid) license key
  * @param string $slug        The slug. This is either the plugin main file path or the theme slug.
  * @param string $version     The current plugin or theme version
  * @param string $author      (optional) The item author.
  */
 public function __construct(Yoast_Product $product, $license_manager)
 {
     $this->product = $product;
     $this->license_manager = $license_manager;
     // generate transient names
     $this->response_transient_key = $this->product->get_transient_prefix() . '-update-response';
     $this->request_failed_transient_key = $this->product->get_transient_prefix() . '-update-request-failed';
     // maybe delete transient
     $this->maybe_delete_transients();
 }