Former President Obama spoke candidly Thursday to a room of 100 donors who paid top dollar to see him speak, telling the room that “everybody needs to chill out” about the differences among the 2020 Democratic candidates.

“Everybody needs to chill out about the candidates,” Obama said to a crowd of about 100 Democratic donors who had paid thousands to listen to his talk in Silicon Valley, according to the Mercury News. “But gin up about the prospect of rallying behind whoever emerges from this process and making sure we’re hitting the ground running.”

Speaking with Democratic National Committee Chairman Tom PerezThomas Edward PerezClinton’s top five vice presidential picks Government social programs: Triumph of hope over evidence Labor’s 'wasteful spending and mismanagement” at Workers’ Comp MORE following the fifth installment of Democratic debates Wednesday night, Obama said he doesn’t care if voters don’t think the eventual nominee is the “perfect” candidate who agrees with them on all important issues.

“The choice is so stark and the stakes are so high that you cannot afford to be ambivalent in this race,” he said.

Obama gave a warning to the slate of candidates that simply getting the Democratic base to turn out to vote next year may not be enough to beat President TrumpDonald John TrumpApple CEO Tim Cook promises to fight for DACA, user privacy DOJ urges Supreme Court to side with Trump in ongoing legal battle over tax returns Giuliani associate willing to inform Congress of meeting between Nunes and former Ukrainian official: report MORE.

“We are not going to win just by increasing the turnout of people who already agree with us completely on everything, which is why I’m always suspicious of purity tests during elections,” he said. “You know what? The country’s complicated.”

The former president and avid basketball fan made a reference to NBA star Stephen Curry, who was in attendance, and his team the Golden State Warriors.

He said the Warriors “won a lot of championships” but they only got there after years of improvement and hard work, comparing their path to that of a candidate who overcomes obstacles to win the presidency.

“It is a necessary process and it will make whoever emerges better,” Obama said, noting his own competitive primary and presidential race in 2008. “I got knocked around pretty good.”

Tickets for the fundraiser in Silicon Valley, Obama’s second event of the day in the area, cost $10,000 to get into the event, $35,000 for a photo with Obama and up to $355,000 for a VIP reception and a premium convention package, according to the Mercury News.

Obama gave a speech Thursday morning at Salesforce’s annual conference Dreamforce.