What password is sent when a router does not have a password set?

I promise this is not a hypothetical question. I am trying to use this GitHub repo - https://github.com/braineo/airport-bssid The latest OS X version does not allow specifying the BSSID so I am using a SSID / channel workaround. However, the router I am trying to connect to is open and does not have a password (I don't have any way of disabling). Thus the script requests "Input WiFi password" and nothing works. I have tried [no entry] and hitting enter, a pair of quotes ""+enter, [one space]+enter. Happy to hear and try some other ideas. Thanks!