docs: def getReffs(self, level: int=1, subreference: CtsReference=None) -> CtsReferenceSet:
          """ CtsReference available at a given level
  
          :param level: Depth required. If not set, should retrieve first encountered level (1 based)
          :param subreference: Subreference (optional)
          :returns: List of levels
          """
  
          if not subreference and hasattr(self, "reference"):
              subreference = self.reference
          elif subreference and not isinstance(subreference, CtsReference):
              subreference = CtsReference(subreference)
  
          return self.getValidReff(level=level, reference=subreference)