code: def un_priority(op,val):
    "unary expression order-of-operations helper"
    if isinstance(val,BinX) and val.op < op: return bin_priority(val.op,UnX(op,val.left),val.right)
    else: return UnX(op,valf un_priority(op,val):
    "unary expression order-of-operations helper"
    if isinstance(val,BinX) and val.op < op: return bin_priority(val.op,UnX(op,val.left),val.right)
    else: return UnX(op,val)
docs: unary expression order-of-operations helper