[Tutor] how to expand "../../myfile"

[Alex Kleider]

Is there a function that can return the full path name when provided 
with something along the lines of
"../../myfile"?

Just to be able to glean the current working directory would suffice. (I 
could use a shell command if I had to but was hoping it could be done 
all within Python.

(python 2.7 on Ubuntu 12.4)

I've searched the os.path and glob modules to no avail.