Python: If file not found try looking for different filename
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**Problem:** 

I have code that looks for a file and open it. By default it looks for file that starts with `#######` (each # being a number). 

Problem is sometimes the file name is `##-#####` and other times `#####`.

I would like a way if the file cannot be found try looking for the other two ways the file could be written.

An IOError exception happens when the file is not found. What I was thinking was to have an except statement that says:

    except File2:
        Look for ##### in  myfindFileFunction()
        if file is still not found run except File3
    except File3:
        Look for ##-#### in myfindFileFuction()
    except:
        print "File not found"

What I am not sure of is how to set up custom exception to work this way, and/or if there is a more pythonic way to do this altogether... 

Would setting up a pattern or the three possible file names and iterate thought each until the file is found work better?