import cadquery as cq
w0=cq.Workplane('ZX',origin=(0,2,0))
r=w0.workplane(offset=-49/2).moveTo(20,-32).box(50,36,49).union(w0.sketch().arc((-18,-15),(-17,-13),(-18,-11)).close().assemble().finalize().extrude(23)).union(w0.sketch().segment((-45,-16),(-16,-16)).segment((-16,-35)).arc((-11,6),(-45,-16)).assemble().reset().face(w0.sketch().segment((-45,47),(-35,11)).segment((-23,15)).segment((-32,50)).close().assemble()).finalize().extrude(44))