class_docstr: the OS/2 table
class_docstr_tok: ["the","OS\/2","table"]
code: def updateFirstAndLastCharIndex(self, ttFont):
      if "cmap" not in ttFont:
          return
      codes = set()
      for table in getattr(ttFont["cmap"], "tables", []):
          if table.isUnicode():
              codes.update(table.cmap.keys())
      if codes:
          minCode = min(codes)
          maxCode = max(codes)
          # USHORT cannot hold codepoints greater than 0xFFFF
          self.usFirstCharIndex = min(0xFFFF, minCode)
          self.usLastCharIndex = min(0xFFFF, maxCode)
  
imports: from fontTools.misc import sstruct
  from fontTools.misc.roundTools import otRound
  from fontTools.misc.textTools import safeEval, num2binary, binary2num
  from fontTools.ttLib.tables import DefaultTable
  import bisect
  import logging
label_desc: Use image node_id 5 for calling the table_O_S_2f_2 obj's underlying member method code with example usage: obj.updateFirstAndLastCharIndex(ttFont) without return types