I understand the four lines below:

```
import bpy
import numpy as np
from sys import argv
from os import *

```

But I've never seen the following lines:

```
from . uisun import *
from . hdr import sunposition

```

What about the dot? Does it refer to the position in the directory or something else?
The files *uisun.py*, *sunposition.py*, *hdr.py* are in the same directory within *\_\_init\_\_.py* which contains the code above.
By the way, this comes from a [Blender](http://www.blender.org/) addon.