How to handle class instance that send through HTTP request?

I have the class:

class ApplicationServer(BaseHTTPRequestHandler):
    def do_POST(self):
        try:
            content_type, post_dict = parse_header(self.headers['content-type'])
            if content_type == 'multipart/form-data':
                post_data = parse_multipart(self.rfile, post_dict)
            elif content_type == 'application/json':
                length = int(self.headers['content-length'])
                post_data = parse_qs(self.rfile.read(length), keep_blank_values=1)
            else:
                post_data = {}

            new_data = {key.decode(): val[0].decode() for key, val in post_data.items()}
            ......

I’m sending through HTTP request class instance, But in the do_POST method it’s receiving as bytes and doing decode() convert it to string, my question is there any way to convert back to class instance?

The way that doing request:

if __name__ == '__main__':
    for i in range(11):
        order = Order(100, "Buy")
        status = requests.post("http://localhost:8000", data={"order": order}, headers={'Content-Type': 'application/json'})