Yes, Julia has multimethods. This is called out in the article:
> Open functions (functions that can be extended with new pattern-matches), open data-types (data types that can be extended with new patterns), and MultiMethods ('open' specialized polymorphic functions with 'open' set of classes), and PredicateDispatching, are all viable approaches.
> Open functions (functions that can be extended with new pattern-matches), open data-types (data types that can be extended with new patterns), and MultiMethods ('open' specialized polymorphic functions with 'open' set of classes), and PredicateDispatching, are all viable approaches.