'``c*x**e -> c,e`` where x can be any symbolic expression.'

def as_coeff_exponent(self, x):

    from sympy import collect
    s = collect(self, x)
    (c, p) = s.as_coeff_mul(x)
    if (len(p) == 1):
        (b, e) = p[0].as_base_exp()
        if (b == x):
            return (c, e)
    return (s, S.Zero)
