docs: def hasReservationResponse(self, pid, subject, vendorSpecific=None):
          """CNCore.registerSystemMetadata(session, pid, sysmeta) → Identifier CN
          INTERNAL.
  
          CNCore.hasReservation(session, pid) → boolean
          https://releases.dataone.org/online/api-documentation-v2.0.1/apis/CN_APIs.html#CNCore.hasReservation
  
          Args:
            pid:
            subject:
            vendorSpecific:
  
          Returns:
  
          """
          return self.GET(['reserve', pid, subject], headers=vendorSpecific)