How can I search for a keycloak user that contains part of a multi-valued attribute

KeyCloak supports multi-valued attributes. If I call the function session.users().searchForUserByUserAttributeStream(realm, 'some-multi-valued-attr', singleValue), will it return every user that contains the single value anywhere in the multi-valued attribute, or will it look for just the first value, or does it expect me to pass the entire multi-valued value?