def parameters(self, parameters, locations=None):
        """
        Endpoint parameters registration decorator.
        """
        def decorator(func):
            if locations is None and parameters.many:
                _locations = ('json', )
            else:
                _locations = locations
            if _locations is not None:
                parameters.context['in'] = _locations

            return self.doc(params=parameters)(
                self.response(code=HTTPStatus.UNPROCESSABLE_ENTITY)(
                    self.WEBARGS_PARSER.use_args(parameters, locations=_locations)(
                        func
                    )
                )
            )

        return decorator
Endpoint parameters registration decorator.