code: def seek(self, pos, whence=os.SEEK_SET):
          
          if whence == os.SEEK_SET:
              new_pos = pos
          elif whence == os.SEEK_CUR:
              new_pos = self.__position + pos
          elif whence == os.SEEK_END:
              new_pos = int(self.length) + pos
          else:
              raise IOError(22, "TxMongo: invalid value for `whence`")
  
          if new_pos < 0:
              raise IOError(22, "TxMongo: invalid value for `pos` - must be positive")
  
          self.__position = new_pos
docs: Set the current position of this file.
  
          :Parameters:
           - `pos`: the position (or offset if using relative
             positioning) to seek to
           - `whence` (optional): where to seek
             from. :attr:`os.SEEK_SET` (``0``) for absolute file
             positioning, :attr:`os.SEEK_CUR` (``1``) to seek relative
             to the current position, :attr:`os.SEEK_END` (``2``) to
             seek relative to the file's end.