When opening a ssl-wraped socket, I get the error `ssl.SSLError: [SSL: UNKNOWN_PROTOCOL] unknown protocol (_ssl.c:581)`

The server is running TLSv1.1

My code is

```
import socket, ssl
uw = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s = ssl.wrap_socket(uw, ssl_version=ssl.PROTOCOL_TLSv1_1)
s.connect((host, port))

```

I can't figure it out. I've tried using a cacert file and get the same error.

```
s = ssl.wrap_socket(uw, ca_certs="cacert.pem", cert_reqs=ssl.CERT_REQUIRED)

```