import cadquery as cq
w0=cq.Workplane('XY',origin=(0,0,-19))
r=w0.sketch().push([(-23,12)]).rect(2,2).push([(-23,49)]).rect(2,2).finalize().extrude(21).union(w0.workplane(offset=25/2).moveTo(22,-39.5).box(42,21,25)).union(w0.workplane(offset=39/2).moveTo(-22.5,-1).box(41,34,39))