+ """
+ Open a connection to the protection server. A PTS object is
+ essentially a handle to talk to the server in a given cell.
+
+ cell defaults to None. If no argument is passed for cell, PTS
+ connects to the home cell.
+
+ sec is the security level, an integer from 0 to 3:
+ - 0: unauthenticated connection
+ - 1: try authenticated, then fall back to unauthenticated
+ - 2: fail if an authenticated connection can't be established
+ - 3: same as 2, plus encrypt all traffic to the protection
+ server
+ """