How to add a legend in a Mathematica Graphics package?

Suppose that I have

Graphics[ {{Point[{0,1}], Black},{Point[{1,1}], Blue}}] which plots a black point and a blue point next to each other.

Now, I want to add a legend as with PlotLegend giving a small black box and the name "a" and a small blue bog and the name "b".

Legends do not seem to be in the options package and I can apparently not just add PlotLegend in the end since it is not compatible with graphics.