code: def _Device_recordVarIdx(self, s):
      """Add VarIdx in this Device table (if any) to the set s."""
      if self.DeltaFormat == 0x8000:
          s.add((self.StartSize << 16) + self.EndSize)
  
imports: from fontTools.misc.roundTools import noRound, otRound
  from fontTools.misc.intTools import bit_count
  from fontTools.ttLib.tables import otTables
  from fontTools.varLib.models import supportScalar
  from fontTools.varLib.builder import buildVarRegionList, buildVarStore, buildVarRegion, buildVarData
  from functools import partial
  from collections import defaultdict
  from heapq import heappush, heappop
label_desc: Use image node_id 8 for calling a global function with example usage: _Device_recordVarIdx(s) without return types