code: def Seek(self, offset, whence=os.SEEK_SET):
      
  
      if whence == os.SEEK_SET:
        self._offset = offset
      elif whence == os.SEEK_CUR:
        self._offset += offset
      elif whence == os.SEEK_END:
        self._offset = self._length + offset
      else:
        raise ValueError("Invalid whence argument: %s" % whence)
docs: Moves the reading cursor.