Endpoint used to retrieve class hierarchy data relative to sourceClass. Behaviour depends on given parameters.

1. If the targetClass is given, but is out of reach (maximum distance of steps, unlimited if not set), an empty list is returned. If it is in reach, then the class hierarchy between sourceClass and targetClass is returned, i.e., all classes which satisfy the following criteria:

• path from sourceClass to targetClass containing it is at most steps long
• is a subclass of targetClass
• is superclass of sourceClass

2. Otherwise return return either superclasses or superclasses (see direction parameter) of sourceClass with a maximal distance of steps, or all super-/subclasses if steps is not given.