Sen. Bernie Sanders (I-Vt.) has made it clear his 2020 campaign isn't funded by billionaires.

Except for a little while, it was. Marta Thoma Hall, the wife of a billionaire inventor, gave $470 to Sanders' campaign this summer — and when Sanders' team realized, they promptly returned it, Forbes reports.

Hall's husband David Hall, who "doesn't have as much of an interest in politics," holds a patent on a self-driving car sensor, and his stake in the Velodyne company has recently been valued at over $1 billion, Forbes writes. That essentially makes Hall a billionaire too — and the only one Forbes could find who donated to Sanders' campaign. She's also given around $500 to some other Democratic contenders, including Sen. Kamala Harris (D-Calif.), and says she wasn't even aware of the $2,800 individual limit on single campaign donations.

Sanders' campaign, meanwhile, makes it clear his website is "paid for by Bernie 2020 (not the billionaires). He's also publicly claimed billionaires "shouldn't exist." So when Forbes asked why there was a billionaire on his donor list, a Sanders spokesperson thanked the publication and said it would be "returning Ms. Hall's contributions."

Hall found the return of her money "disappointing," she said. "I don't understand why they would do that. That's ridiculous," she told Forbes. Still, one has to respect the adherence to the brand. Kathryn Krawczyk