I want to estimate the number of zeros for the function, by using Rouche's theorem.

$\displaystyle f(z)=z^2e^z-z$ in the region $\displaystyle D(0,2)$, which is a disc around 0 with radius 2.

I can only find and perform easy examples for polynomials, this one has been bugging me for a while now. No clue in what direction I have to look to pick a function to compare $\displaystyle f(z)$ with.