# is there anyone able to develop this series in order to get the following equality?

$\sum_{i=1}^\infty (1-\alpha)_{(i-1)}*\frac{\varepsilon^i}{i!}$ = $\frac{1-(1-\varepsilon)^{\alpha}}{\alpha}$

where $(1-\alpha)_{(i-1)}$ is the Pochammer symbol or rising\ascending factorial.

Can anyone explain me this equality? Thanks