Here Student is a class containing get() and show(). We have defined get() and show()
function. It is noted that inside a class when we are defining a function, that function must
take self argument. The keyword self represent current instance(object).
We have taken s as object of type Student, then get() and show() have invoked by s. It is
pointing that when get() and show() invoking by s, then get() and show() definition
executing, such concept is also known as message passing.