[FE-discuss] schema and at least one of the validators is not empty

[Carl S. Yestrau Jr.]

class AtLeastOneOfThese(formencode.Schema):
a = validators.String(not_empty=False)
b = validators.String(not_empty=False)
c = validators.String(not_empty=False)
# how do I create a chained validator so even though a, b, c are
optional at least one of a, b or c is not_empty?