LOS ALTOS HILLS, Calif. (AP) — Former President Barack Obama is warning Democrats against adopting “purity tests” in the presidential primary and alienating voters needed to defeat President Donald Trump in the general election.

Obama spoke Thursday before about 100 donors during a question-and-answer session with Democratic National Committee Chairman Tom Perez in Los Altos Hills, California. The event came a day after the fifth Democratic presidential primary, which featuring 10 candidates.

Obama urged Democrats to “chill out,” saying, “The truth of the matter is that every candidate on that stage believes we should provide” better health care and education and address climate change.

The event was held at the home of Karla Jurvetson, a Silicon Valley philanthropist. A senior party official said the event was expected to raise more than $3 million for the DNC.