docs: def encode_sid(cls, secret, sid):
          """Computes the HMAC for the given session id."""
  
          secret_bytes = secret.encode("utf-8")
          sid_bytes = sid.encode("utf-8")
  
          sig = hmac.new(secret_bytes, sid_bytes, hashlib.sha512).hexdigest()
          return "%s%s" % (sig, sid)