code: def _unpack_from(buf, format_s, count=None, little_endian=True):
      
  
      if count is not None:
          assert count > 0
          format_s = '%i%s' % (count, format_s)
  
      if little_endian is True:
          format_s = '<' + format_s
      else:
          format_s = '>' + format_s
  
      size = struct.calcsize(format_s)
      res = struct.unpack_from(format_s, buf.read(size))
  
      if count is not None:
          return res
      else:
          return res[0]
docs: Read a binary format from the buffer.