importing a sibling module

[Clark C . Evans]

On Fri, Jan 04, 2002 at 11:14:58AM +0100, Alex Martelli wrote:
| >     folder    files
| > /zz/V13/lib  tool.py
| > /zz/V13/app  prog.py
| > /zz/V14/lib  tool.py
| > /zz/V14/app  prog.py
| ...
| > What I'd like to do, within prog.py is "import ../lib/tool.py"
... 
| import os, sys, imp
| app_dir, appfilename = os.path.split(sys.argv[0])
| lib_dir = os.path.join(app_dir,'../lib')
| imp.load_module('tool', *imp.find_module('tool',[libdir]))

Thank you Alex; unfortunately, this returns an app_dir of '' 

Is there any way to ask a module for it's pathname?  Say
__mypath__ returns this.  Then I could pop "app" from the
path, push "lib" on the path and then import tool.py using
the technique you described.

Best,

Clark