** ]{}([@Sch], Theorem 0.0)[**.**]{} [*Let $k, n$ be positive integers such that $n\geq k+0.$ Let $\mathcal F$ be a family of entire functions in a complex domain $D$ such that for every $f\in\mathcal F,$ $(f^n)^{(k)}(z)\ne 0$ for all $z\in D.$ Then $\mathcal F$ is normal on $D.$*]{}  