def validate(self, strict=True):
        """ check if this Swagger API valid or not.

        :param bool strict: when in strict mode, exception would be raised if not valid.
        :return: validation errors
        :rtype: list of tuple(where, type, msg).
        """

        result = self._validate()
        if strict and len(result):
            for r in result:
                logger.error(r)
            raise errs.ValidationError('this Swagger App contains error: {0}.'.format(len(result)))

        return result