class type key =object..end
key is a user/password combination for a certain realmmethod user : stringmethod password : stringmethod realm : stringmethod domain : string list
 Normally, this is just a list with one element. The URI must include
 the protocol scheme, the host name, and "/" as path. The port number
 is optional. Example: "http://localhost/". If the key is applicable
 to all domains, set this to "*".