: str_replace(): Passing null to parameter #2 ($replace) of type array|string is deprecated in
namespace Yoast\WP\SEO\User_Meta\Domain;
* This interface describes a custom meta.
interface Custom_Meta_Interface {
* Returns the db key of the custom meta.
public function get_key(): string;
* Returns the id of the custom meta's form field.
public function get_field_id(): string;
* Returns whether the custom meta is allowed to be empty.
public function is_empty_allowed(): bool;