def parse(self, value):
        """
        Enforce rules and return parsed value
        """
        if self.required and value is None:
            raise ValueError("%s is required!" % self.name)
        elif self.ignored and value is not None:
            warn("%s is ignored for this class!" % self.name)
        elif not self.multi and isinstance(value, (list, tuple)):
            if len(value) > 1:
                raise ValueError(
                    "%s does not accept multiple values!" % self.name
                )
            return value[0]
        elif self.multi and value is not None:
            if not isinstance(value, (list, tuple)):
                return [value]
        return value
Enforce rules and return parsed value