Hundreds of Nigerians celebrate at an intersection in the flashpoint northern city of Kaduna on March 31, 2015 the victory of main opposition All Progressives Congress (APC) presidential candidate Mohammadu Buhari. (Photo by Nichole Sobecki/AFP Photo)

Supporters of the presidential candidate Muhammadu Buhari and his All Progressive Congress hits another supporter with a motorbike during celebrations in Kano, Nigeria March 31, 2015. (Photo by Goran Tomasevic/Reuters)

A group of women laugh at artwork referencing U.S. Republican presidential candidate Donald Trump made by the artist Hanksy and being sold at a temporary store in New York, U.S., June 4, 2016. (Photo by Lucas Jackson/Reuters)

Remote control plane builder Otto Diefffenbach III launches his plane resembling U.S. Presidential candidate Hillary Clinton in Carlsbad, California, U.S. September 15, 2016. (Photo by Mike Blake/Reuters)

Supporter Mette Peluce, 11, waits for U.S. Democratic presidential candidate Bernie Sanders to speak in East Los Angeles, California, U.S. May 23, 2016. (Photo by Lucy Nicholson/Reuters)

A supporter of Republican U.S. presidential candidate Donald Trump dresses in a Trump costume at a rally with supporters in Albuquerque, New Mexico, U.S., May 24, 2016. (Photo by Jonathan Ernst/Reuters)

A man demonstrates outside Republican presidential candidate Donald Trump's news conference at Trump Tower in New York, U.S., May 31, 2016. (Photo by Shannon Stapleton/Reuters)

Colorado Gov. John Hickenlooper shows off his socks--one with Democratic presidential candidate Bernie Sanders and the other with Republican candidate Donald Trump – before entering his former brewpub for a book signing event to mark the release of his autobiography Thursday, May 26, 2016, in Denver. Hickenlooper, who is term-limited, is doing book talk rounds this week, reviving speculation that he is positioning himself to join Hillary Clinton's presidential campaign ticket. (Photo by David Zalubowski/AP Photo)