Rome's newly elected mayor Virginia Raggi, of 5-Star Movement, gestures during a news conference in Rome, Italy June 20, 2016. REUTERS/Remo Casilli

Formula One - Singapore Grand Prix - Marina Bay, Singapore - 18/9/16 Mercedes' driver Nico Rosberg of Germany arrives ahead of the race. REUTERS/Edgar Su

Formula One - F1 - Singapore Grand Prix - Marina Bay, Singapore- 18/9/16 Mercedes' Nico Rosberg of Germany leads after the start of the race. REUTERS/Edgar Su

Formula One - F1 - Singapore Grand Prix - Marina Bay, Singapore- 18/9/16 Mercedes' Nico Rosberg of Germany leads Red Bull's Daniel Ricciardo of Australia during the race. REUTERS/Edgar Su

U.S. Attorney for New Jersey Paul J. Fishman attends a news conference in Newark, New Jersey, U.S. on July 14, 2016. REUTERS/Eduardo Munoz/File Photo

David Samson, the former chairman of the Port Authority, exits Newark federal court in New Jersey, U.S. on July 14, 2016. REUTERS/Eduardo Munoz/File Photo

New Jersey Governor Chris Christie's chief of staff Kevin O'Dowd testifies at a hearing before a joint legislative committee in regards to the Bridgegate scandal in Trenton, New Jersey, U.S. on June 9, 2014. REUTERS/Charles Mostoller/File Photo

New Jersey Governor Chris Christie reacts to a question during a news conference in Trenton, New Jersey, U.S. on March 28, 2014. REUTERS/Eduardo Munoz/File Photo