Get Rotation of a Group or Object

[conzar]

Is it possible to get the rotation of an object relative to the origin? Simular to the get_centre function.

For example, say you have 2 boxes in a group. You rotate that group on the x-axis by pi. Is there a way that I can get the rotation about the x,y,z axis? So for the example here I should get rotation (3.14,0,0).
If we rotate the group again in the same direction on the same axis by pi again, then we should get [0,0,0].