+
+def find_next_free (dest, too_many=100):
+ extra = 0;
+ orig_dest = dest;
+ while os.path.exists(dest) and extra < too_many:
+ dest = orig_dest + '.' + repr(extra);
+ extra = extra + 1;
+ if extra >= too_many:
+ raise tried_too_hard_exc;
+ return dest;
+
+################################################################################