code: def _parse_ppt_segment(self, fptr):
          
          offset = fptr.tell() - 2
  
          read_buffer = fptr.read(3)
          length, zppt = struct.unpack('>HB', read_buffer)
          length = length
          zppt = zppt
  
          numbytes = length - 3
          ippt = fptr.read(numbytes)
  
          return PPTsegment(zppt, ippt, length, offset)
docs: Parse the PPT segment.
  
          The packet headers are not parsed, i.e. they remain "uninterpreted"
          raw data beffers.
  
          Parameters
          ----------
          fptr : file object
              The file to parse.
  
          Returns
          -------
          PPTSegment
              The current PPT segment.