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A non-licensed private cab driver working with Uber shows a Uber mobile application in Nairobi on February 4, 2016. (SIMON MAINA/AFP/Getty Images)

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Fentanyl Citrate, a CLASS II Controlled Substance as classified by the Drug Enforcement Agency in the secure area of a local hospital, July 10, 2009. (Joe Amon/The Denver Post via Getty Images)

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San Bernardino shooting suspects Syed Rizwan Farook, 28, and wife Tashfeen Malik, 27, in undated mug shots. (FBI Handout)

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Republican presidential candidate Sen. Ted Cruz (R-TX) speaks to supporters during a campaign event on December 4, 2015 in Johnston, Iowa. (Scott Olson/Getty Images)

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Democratic presidential candidate, Sen. Bernie Sanders (I-VT) speaks during a campaign event at Grand View University January 31, 2016 in Des Moines, Iowa. (Alex Wong/Getty Images)

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Director of National Drug Control Policy Michael Botticelli at the East End Family Resource Center on October 21, 2015 in Charleston, West Virginia. (MANDEL NGAN/AFP/Getty Images)