Declaring an element within the body of a namespace denotes that the element is an owned member of the namespace, i.e., there is an owning membership relationship between the namespace and the member element. The visibility of such membership can be specified using the following keywords:
public (default) - membership is visible outside the namespace.
private- membership is invisible from outside the namespace.
protected- membership is invisible outside the namespace, except in inheritance, where it behaves like public.