code: def GetFormatSpecification(self):
      
      format_specification = specification.FormatSpecification(
          self.type_indicator)
  
      # TODO: add support for signature chains so that we add the 'BZ' at
      # offset 0.
  
      # BZIP2 compressed steam signature.
      format_specification.AddNewSignature(b'\x31\x41\x59\x26\x53\x59', offset=4)
  
      return format_specification
docs: Retrieves the format specification.
  
      Returns:
        FormatSpecification: format specification or None if the format cannot
            be defined by a specification object.