code: def detect_volume_shadow_copies(self):
          
  
          self._make_mountpoint(var_name='vss', suffix="vss", in_paths=True)
  
          try:
              _util.check_call_(["vshadowmount", "-o", str(self.offset), self.get_raw_path(), self._paths['vss']])
          except Exception as e:
              logger.exception("Failed mounting the volume shadow copies.")
              raise SubsystemError(e)
          else:
              return self.volumes.detect_volumes(vstype='vss')
docs: Method to call vshadowmount and mount NTFS volume shadow copies.
  
          :return: iterable with the :class:`Volume` objects of the VSS
          :raises CommandNotFoundError: if the underlying command does not exist
          :raises SubSystemError: if the underlying command fails
          :raises NoMountpointAvailableError: if there is no mountpoint available