Elon Musk, Chairman of SolarCity and CEO of Tesla Motors, speaks at SolarCity's Inside Energy Summit in Manhattan, New York October 2, 2015. REUTERS/Rashid Umar Abbasi/File Photo

U.S. President Barack Obama speaks at the Our Ocean Conference at the State Department in Washington, D.C., U.S., September 15, 2016. REUTERS/Kevin Lamarque

Burkina Faso's President Blaise Compaore poses during an European Union (EU)-Africa summit in Brussels April 2, 2014. REUTERS/Francois Lenoir

A part of the signage at the main gate of The Walt Disney Co. is pictured in Burbank, California, May 7, 2012. REUTERS/Fred Prouser

Arkansas governor Mike Beebe looks on during a Martin Luther King Jr. service in Little Rock, Arkansas in this January 15, 2013 Governor's office handout photo obtained by Reuters March 6, 2013. REUTERS/Arkansas Governor's Office/Handout

European Council President Donald Tusk (3rdL), European Commission President Jean-Claude Juncker (2ndR) and European Parliament President Martin Schulz (L) pose for a group photo with Slovakia's Prime Minister Robert Fico (C), Slovakia's President Andrej Kiska (3rdR) and Speaker of the Slovakia's National Council Andrej Danko (2ndL) at the Government office ahead of the upcoming European Union summit- the first one since Britain voted to quit- in Bratislava, Slovakia, September 15, 2016. REUTERS/Yves Herman

European Council President Donald Tusk (3rdL), European Commission President Jean-Claude Juncker (2ndR) and European Parliament President Martin Schulz (L) pose for a group photo with Slovakia's Prime Minister Robert Fico (C), Slovakia's President Andrej Kiska (3rdR) and Speaker of the Slovakia's National Council Andrej Danko (2ndL) at the Government office ahead of the upcoming European Union summit- the first one since Britain voted to quit- in Bratislava, Slovakia, September 15, 2016. REUTERS/Yves Herman

European Union leaders pose for a family photo during the European Union summit- the first one since Britain voted to quit- in Bratislava, Slovakia, September 16, 2016. REUTERS/Leonhard Foeger