If $Z_n\overset{d}{\rightarrow}Z,\ Y_n\overset{d}{\rightarrow}a$ where $a\in\mathbb{R}$ where the CDF of Z is continuous then $Y_nZ_n\overset{d}{\rightarrow}aZ$
I tried proving using a similliar proof to Slutsky's theorem with sum and got that if I prove
$$ \mathbb{P}(|Z_n(Y_n-a)|>\delta)\rightarrow 0$$
I finish.
I know that $Y_n \overset{\mathbb{P}}{\rightarrow}a$ So I feel like I am close to the answer, I havn't used the fact that the CDF of Z is continuous yet, so I feel like I'm supposed to use it here.
Is there a way to complete the proof?
If not, can I get a hint how to solve the problem and how to use the fact that the CDF of Z is continuous.
Thank you,