code: def op_callsubr(self, index):
      self.localSubrs._used.add(self.operandStack[-1] + self.localBias)
      psCharStrings.SimpleT2Decompiler.op_callsubr(self, index)
  
imports: from fontTools.misc import psCharStrings
  from fontTools import ttLib
  from fontTools.pens.basePen import NullPen
  from fontTools.misc.roundTools import otRound
  from fontTools.misc.loggingTools import deprecateFunction
  from fontTools.subset.util import _add_method, _uniq_sort
label_desc: Use image node_id 2 for calling the _MarkingT2Decompiler obj's underlying member method code with example usage: obj.op_callsubr(index) without return types