What is the best way to disallow empty arrays/lists?

[tgross35]

In the doc, it's mentioned that validating an empty list [] will return true.

To do that, you need Schema(Or({int:int}, {})). This is unlike what happens with lists, where Schema([int]).is_valid([]) will return True.

What is the best way to disallow this? The best thing I can think of now is to import Use and call something that raises an error if nonempty. However, this isn't good for anything recursive.

[nuriel77]

Had the same requirement.
Managed to get this working:

Schema({
  "some_list": And(lambda n: len(n), [Regex(URL_REGEX)])
})