### Expected value of random variables

I'm new to SAGE and just getting my feet wet. Would greatly appreciate if someone could point me to how to calculate the following using SAGE:

Say I have an event drawn from a Poisson distribution that happens on average once a year. I'd like to define a random variable and then calculate the following:

Probability the event will occur after 1 month (1/12th of a year)

Probability the event will not occur for 2 years but will occur during the third year.

I've searched unsuccessfully for how to do this and would greatly appreciate any help.