@_sympifyit('g', NotImplemented)
    def __rsub__(f, g):
        if not g.is_Poly:
            try:
                g = f.__class__(g, *f.gens)
            except PolynomialError:
                return g - f.as_expr()

        return g.sub(f)
dataset/ETHPy150Open sympy/sympy/sympy/polys/polytools.py/Poly.__rsub__/original