In this exercise you must use the Observer design pattern.
This exercise is very similar to the example NotifyPropertyChangeSmallExample.
Read and understand the example NotifyPropertyChangeSmallExample.
Create a new Solution in Visual Studio. Give the solution an appropriate name like ObserverNotifyPropertyChange
Create a class Teacher with properties like Name, Salary, etc.
The Teacher class must implement the interface INotifyPropertyChanged.
After a change in the properties value all Observers must be notified.
Make a Main(...) method that make a Teacher object and add at least one observer to the object.
Make a Unit test to check that the Teacher object really sends events when the property values are changed.
The Teacher class must implement the interface INotifyPropertyChanging.
Try with Main() + Unit test.