code: def _context_names():
      
      import inspect
  
      from renku.models import provenance
      from renku.models._jsonld import JSONLDMixin
  
      for name in dir(provenance):
          cls = getattr(provenance, name)
          if inspect.isclass(cls) and issubclass(cls, JSONLDMixin):
              yield name
docs: Return list of valid context names.