Preventing 'bad' filenames from raising errors in os.path

[python at bdurham.com]

Bad file names, i.e. filenames the OS considers illegal, will cause
functions in the os.path module to raise an error.

Example:

import os.path
print os.path.getsize( 'c:/pytest/*.py' )

On Windows XP using Python 2.5.2 I get the following traceback:

Traceback (most recent call last):
  File "<string>", line 74, in run_nodebug
  File "<Module1>", line 3, in <module>
  File "C:\Python\lib\ntpath.py", line 228, in getsize
    return os.stat(filename).st_size
WindowsError: [Error 123] The filename, directory name, or volume label
syntax is incorrect: 'c:/pytest/*.py'

Since there are many places a user can enter a path name (interactively,
via config files, etc) in most applications, is there an os sensitive
function that can be used to detect bad file names?

As a matter of best practice, how do you wrap your use of file and path
names to prevent unexpected failures? (There has to be a better
alternative than try/except blocks around each use of an os.path
function in one's code?)

Thanks,
Malcolm