def _expt__requestItem(self):
    """Return set of request item item identifiers for request items linked directly or indirectly to this experiment"""

    s = set()
    for u in [self.uid,self.mip,self.egid]:
      if 'requestItem' in self._inx.iref_by_sect[u].a:
        for x in self._inx.iref_by_sect[u].a['requestItem']:
          s.add(x)
    return s