4. Given that $f(x)$ is an odd function defined on $(-1,1)$, and it is monotonically decreasing on the interval $[0,1)$, and $f(1-a)+f\left(1-a^{2}\right)<0$, the range of real number $a$ is $\qquad$ .
4. $(0,1)$. $f(1-a)a^{2}-1,$\end{array}\right.$ get $a \in(0,1)$.
