In a case study discussed , I am confused about the multiplicity between lease and room. I as per my point of view, a room will be under zero or one lease agreement at a time(legally). A room can have multiple records of lease agreement(some may be date expired,so not valid OR some may be contracted for a future date ie effective from a future date). But at a particular point of time, a room can have maximum one lease agreement right.. Kindly clarify