@classmethod
def eval(cls, arg):
    if (arg is None):
        return None
    if arg.is_zero:
        return S.One
    exp_arg = sympy.exp.eval(arg)
    if (exp_arg is not None):
        return ((exp_arg - S.One) / arg)
@classmethod
def eval(cls, arg):
    if (arg is None):
        return None
    if arg.is_zero:
        return S.One
    exp_arg = sympy.exp.eval(arg)
    if (exp_arg is not None):
        return ((exp_arg - S.One) / arg)