Port: Is it needed?

An element can be declared as : 

option 1:
```
context c1
   public media media1
   end
end
```
option 2:
```
context c1
   media media1 [public, etc]
   end
end
```
option 3:
```
context c1
private:
   media media1
   end
public:
   media media1
   end
end
```

And then the elements external to **c1** have access to the **media1**.