def _invert_complex(f, g_ys, symbol):

    if f == symbol:
        return (f, g_ys)

    n = Dummy('n')

    if f.is_Add:
        # f = g + h
        g, h = f.as_independent(symbol)
        if g is not S.Zero:
            return _invert_complex(h, imageset(Lambda(n, n - g), g_ys), symbol)

    if f.is_Mul:
        # f = g*h
        g, h = f.as_independent(symbol)

        if g is not S.One:
            return _invert_complex(h, imageset(Lambda(n, n/g), g_ys), symbol)

    if hasattr(f, 'inverse') and \
       not isinstance(f, TrigonometricFunction) and \
       not isinstance(f, exp):
        if len(f.args) > 1:
            raise ValueError("Only functions with one argument are supported.")
        return _invert_complex(f.args[0],
                               imageset(Lambda(n, f.inverse()(n)), g_ys), symbol)

    if isinstance(f, exp):
        if isinstance(g_ys, FiniteSet):
            exp_invs = Union(*[imageset(Lambda(n, I*(2*n*pi + arg(g_y)) +
                                               log(Abs(g_y))), S.Integers)
                               for g_y in g_ys if g_y != 0])
            return _invert_complex(f.args[0], exp_invs, symbol)

    return (f, g_ys)
Helper function for _invert.
dataset/ETHPy150Open sympy/sympy/sympy/solvers/solveset.py/_invert_complex