https://github.com/sagemath/sage/blob/c4363fc97eb67fb08073ea37ef88d633e9feb160/src/sage/plot/graphics.py#L1129
def __add__(self, other):
"""
If you have any Graphics object G1, you can always add any other
amount of Graphics objects G2,G3,... to form a new Graphics object:
``G4 = G1 + G2 + G3``.