Returns True if input is an object of a defined type:

Returns False if input is an object of a type which is not defined:

Matches Links:

Matches packets:

An empty association is not a packet because it is missing the Type key:

Returns True if input is an object of a defined Model type:

Returns True for an Object with only an ID:

Returns True for a Model with only an ID:

Matches Links to fields:

Matches a Link with a link-id and without a Field:

Matches Links with specific ids: