1=begin
 2Imagine you have a call centre with three levels of employees: respondent, manager, and director.
 3An incoming telephone call must be first allocated to a respondent who is free. 
 4If the respondent can't handle the call, he or she must escalate the call to a manager. 
 5If the manager is not free or not able to handle it, then the call should be escalated to a director.
 6Design the classes and data structures for this problem. Implement a method "dispatch_call()" which
 7assigns a call to the first available employee.
 8=end
 9
10describe "call centre" do
11end