[DGD] n00b question on mappings

[Kurt Nordstrom]

Okay, so, I'm not sure I'm understanding mapping syntax, maybe somebody 
can help me out.

Let's say I've got a mapping, "myMap".

I initialize myMap before I use it, with myMap = ([ ]);

If I want to add a value to myMap, am I able to simply do myMap["age"] = 
18, or do I need to do myMap += (["age" : 18 ])?

Simple question, I guess, but I'm confused somewhere down the line.

Thanks.