import cadquery as cq
w0=cq.Workplane('ZX',origin=(0,-50,0))
r=w0.sketch().segment((-20,-16),(-7,-16)).segment((-7,-34)).segment((15,-34)).segment((15,-16)).segment((20,-16)).segment((20,34)).segment((-20,34)).close().assemble().finalize().extrude(100)