import cadquery as cq
w0=cq.Workplane('XY',origin=(0,0,-15))
r=w0.sketch().arc((-50,42),(-48,41),(-49,43)).arc((-49,42),(-50,42)).assemble().finalize().extrude(-31).union(w0.sketch().segment((-23,-11),(-16,-19)).arc((50,-6),(-17,-4)).close().assemble().finalize().extrude(61))