Fixed string formatting in the length validator

[brukhabtu]

The length validator would return
'Value must be no more than %(max)d characters long'
without substituting min/max. Replacing with new style string formatting has fixed this.

[aconrad]

Can you illustrate this problem a little more, I'm having a hard time understanding what the problem is exactly. Is this a scoping / closure issue with the namespace of the builtins min and max? If yes, why not change the function's params to be min_length and max_lenght?

I'm not against using format(), I'm just trying to understand how format fixes your problem.