import cadquery as cq
w0=cq.Workplane('YZ',origin=(35,0,0))
r=w0.sketch().segment((-42,-50),(42,-50)).segment((42,-8)).arc((-3,17),(-42,50)).close().assemble().push([(-18,-18.5)]).rect(44,15,mode='s').finalize().extrude(-71)