ComplexObjectPropertyDescriptor.unbind Method
        
 Unsubscribe an event. if handler is specified, unsubscribe that handler.
 if no parameters are specified, unbind everything.
 
         
        Parameters
        
            - eventName
            
 
            - 
                
Type: String
(Optional) The event name of the event. 
            - handler
            
 
            - 
                
Type: function
(Optional) The event handler that needs to be unsubscribed.