Source code for schema.validate

class In(object):
    error_messages = {"validator_failed": "Id not found."}

    @staticmethod
    def apply(src, negation=False):
        def data():
            return src() if callable(src) else src

        if negation:
            return lambda field: field not in data()
        else:
            return lambda field: field in data()


class UniqueList(object):
    error_messages = {"validator_failed": "Repeated values."}

    @staticmethod
    def apply(field=None):
        def __get(values):
            if field is not None:
                fields = [value.get(field, None) for value in values]
            else:
                fields = values
            return len(fields) == len(set(fields))

        return __get