Associative Array Non-null initialization

[Kyle G.]

Hi,

I want to declare an AA such that it's starting length is 0, yet, it is 
not null.

For instance:

1 string[int] aa;
2 assert (aa.length == 0);
3 assert (aa is null);
4 aa[100] = "";
5 aa.remove(100);
6 assert (aa.length == 0);
7 assert (aa !is null);

The above runs without error, as it should. Notice that assertions 3 and 
7 are opposite.

However, is there anything shorter/more efficient that I can do 
(preferably on line 1) which would generate an AA which satisfies the 
assertions 6 and 7?

This appears to function in the same way:

string[int] aa = [100:""];
aa.remove(100);
assert (aa.length == 0);
assert (aa !is null);

Thank you.