flask-restx how to create parser from model

def build_parser(schema):
    parser = RequestParser()

    for prop, conf in schema['properties'].items():
        if conf.get('type') == 'string' and conf.get('format') == 'date-time':
            parser.add_argument(prop, type=inputs.datetime_from_iso8601)
        elif conf['type'] == 'integer':
            parser.add_argument(prop, type=int)
        elif conf['type'] == 'boolean':
            parser.add_argument(prop, type=bool, default=False)
        elif conf['type'] == 'array':
            parser.add_argument(prop, default=list, action='append')
     return parser
import functools
import inspect

class Rest:

    def route(api, route_str='', decorators=None):
        decorators = decorators or []

        def wrapper(cls):
            for name, method in inspect.getmembers(cls, inspect.isfunction):
                schema_name = getattr(method, '_schema_name', None)
                if schema_name:
                    schema = getattr(method, '_schema', None)
                    setattr(cls, name, api.expect(api.schema_model(schema_name, schema), validate=True)(method))

            cls.method_decorators = cls.method_decorators + decorators
            return api.route(route_str)(cls) if route_str else cls

        return wrapper

    def schema(schema_name, parse=False):
        def decorator(f):
            f._schema_name = schema_name
            f._schema = get_api_schema(schema_name) # this function reads the json file
            parser = build_parser(f._schema)

            def wrapper(*args, **kwargs):
                if parse:
                    req_args = parser.parse_args()
                    return f(*args, req_args, **kwargs)

                return f(*args, **kwargs)

            return wrapper

        return decorator
@Rest.route(api, '/my_api/')
class MyApi(Resource):

    @Rest.schema('my_api_schema_name', parse=True)
    def post(self, args, id):
        do_something(args['param1'], args['the_date'])