import cadquery as cq
w0=cq.Workplane('ZX',origin=(0,50,0))
r=w0.workplane(offset=-101/2).moveTo(-43,61.5).box(44,77,101).union(w0.sketch().push([(44.5,-57.5)]).rect(41,85).push([(51,-58)]).rect(10,10,mode='s').finalize().extrude(-69))