How can I configure jest-puppeteer to run 2 browsers instances at the same time?

I am using jest with puppeteer and I want to run 2 tests in parallel, meaning that I want 2 headless chrome instances to be opened and running at the same. The problem is that only one browser does the test and the other one doesn't. I am trying to configure the browser setUp, but still haven't figure it out. Do you have any ideas? Thank you!!