from ./.. import

[Hongyi Zhao]

Hi,

See this file:
https://github.com/hongyi-zhao/dotbot/blob/master/dotbot/messenger/
messenger.py

It has the following codes:

from ..util.singleton import Singleton
from ..util.compat import with_metaclass
from .color import Color
from .level import Level

I just cannot figure out why they using the ``from ./.. import'' to 
import modules.

Any hints?