Verifying a database.

Hello, I'm writing a sqlite database accessprogram and I am wondering
how I might be able to verify that a specified file by the user really
is a sqlite database.

I tried:

       try:
           dbcon = sqlite.connect(self.dbpath[0])
           db = dbcon.cursor()
       except:
           print "Database Open Error."

but, it seems that even if the file is a .jpg or .py it still makes
the connection.

Any help would be greatly appreciated!