code: def VarData_addItem(self, deltas, *, round=round):
      deltas = [round(d) for d in deltas]
  
      countUs = self.VarRegionCount
      countThem = len(deltas)
      if countUs + 1 == countThem:
          deltas = list(deltas[1:])
      else:
          assert countUs == countThem, (countUs, countThem)
          deltas = list(deltas)
      self.Item.append(deltas)
      self.ItemCount = len(self.Item)
  
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 2 for calling a global function with example usage: VarData_addItem(deltas) without return types