Documentation errors with filters?

https://rankmath.com/kb/filters-hooks-api-developer/#change-post-schema-data it says:

**
 * Filter to change the schema data.
 * Replace $schmea_type with schema name like article, review, etc.
 * @param array $entity Snippet Data
 * @return array
 */
add_filter( "rank_math/snippet/rich_snippet_{$schema}_entity", function( $entity ) {
 return $entity;
});

In this example you are missing a forward slash, but also you are referencing a variable named $schmea_type

Schema is spelled wrong and doesn’t even have any reference in the function.