text: def get_file_size_unit(unit_type):
      """
      File size unit according to https://en.wikipedia.org/wiki/Kibibyte.
      """
      table = {
          # decimal
          'kb': 10 ** 3,
          'mb': 10 ** 6,
          'gb': 10 ** 9,
          'tb': 10 ** 12,
          'pb': 10 ** 15,
          # binary
          'kib': 1 << 10,
          'mib': 1 << 20,
          'gib': 1 << 30,
          'tib': 1 << 40,
          'pib': 1 << 50,
      }
  
      unit_type = unit_type.lower()
      if unit_type not in table.keys():
          raise TypeError('Invalid unit type')
  
      return table.get(unit_type)
  