code: def __init__(self, chars):
      self.chars = chars
      self.width = bit_count(chars)
      self.columns = self._columns(chars)
      self.overhead = self._characteristic_overhead(self.columns)
      self.items = set()
  
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 1 to create a new _Encoding object from inherited base classes: object with example: obj = _Encoding(chars)