Binding keys: Could you help me to understand?

Hi there,

Could you be so nice and explain what this sentence do? I understand the concept behind (to bind a key to the keyboard) but I do not understand how and the explanation in the reference is not clear.

moveMap.bindObj(getWord(%this.upKey, 0), getWord(%this.upKey, 1), "moveUp", %this);

Thanks in advance
Learner