code: def set_uids(pifs, uids=None):
      
      if not uids:
          uids = [str(hash(dumps(x))) for x in pifs]
      for pif, uid in zip(pifs, uids):
          pif.uid = uid
      return pifs
docs: Set the uids in a PIF, explicitly if the list of UIDs is passed in
      :param pifs: to set UIDs in
      :param uids: to set; defaults to a hash of the object
      :return: