code: def _range2cols(areas):
      
      cols = []
  
      for rng in areas.split(","):
          if ":" in rng:
              rng = rng.split(":")
              cols.extend(lrange(_excel2num(rng[0]), _excel2num(rng[1]) + 1))
          else:
              cols.append(_excel2num(rng))
  
      return cols
docs: Convert comma separated list of column names and ranges to indices.
  
      Parameters
      ----------
      areas : str
          A string containing a sequence of column ranges (or areas).
  
      Returns
      -------
      cols : list
          A list of 0-based column indices.
  
      Examples
      --------
      >>> _range2cols('A:E')
      [0, 1, 2, 3, 4]
      >>> _range2cols('A,C,Z:AB')
      [0, 2, 25, 26, 27]