Wrapper around instance_of, subclass_of, and subproperty_of.
Using this is a bit slower as an additional type check
is needed.
For example: Cat is_a Animal and Nibbler is_a Cat.
Note that contrary to wrapped predicates, is_a/2 requires
the Resource to be ground.
- Arguments:
-
| Resource | - a RDF resource |
| Type | - the type of the resource |