Metropolitan Transit Authority (MTA) Police Officer Keith Flood trains with his K-9 partner Doc, a German Shepherd, inside the “warehouse room” at the new MTA Police Department Canine Training Center in Stormville, New York, U.S., June 6, 2016. (Photo by Mike Segar/Reuters)

Fatima Rezai, 21, a female officer from the Afghan National Army (ANA) practices with a punch bag during an exercise session at at the Kabul Military Training Centre (KMTC) in Kabul, Afghanistan October 23, 2016. (Photo by Mohammad Ismail/Reuters)

Apple CEO Tim Cook discusses the new iPhone 6 and iPhone 6 plus on Tuesday, September 9, 2014, in Cupertino, Calif. The iPhone 6 will have a screen measuring 4.7 inches, while the iPhone 6 Plus will be 5.5 inches. (Photo by Marcio Jose Sanchez/AP Photo)

An anti-government demonstrator argues with a Bolivarian National Police officer during a march toward the headquarters of the national electoral body, CNE, in Caracas, Venezuela, Wednesday, May 18, 2016. Opposition protesters were blocked from reaching the CNE as they demand the government allow it to pursue a recall referendum against Venezuela's President Nicolas Maduro. (Photo by Fernando Llano/AP Photo)

David Colturi of the USA dives from the 27 metre platform during the fifth stop of the Red Bull Cliff Diving World Series in Polignano a Mare, Italy on August 28 2016. (Photo by Dean Treml/ANSA/Red Bull Press Office)

Iraqi army soldiers warm themselves next to a fire near the Qayara air base, south of Mosul, Iraq, Tuesday, November 1, 2016. The U.N. human rights office is lauding efforts by the U.S.-led coalition in the battle against the Islamic State group in Mosul. The office in Geneva says coalition flights over Iraq have largely succeeded in preventing IS from bringing in 25,000 more civilians to the city center, where the militant group has been using people as human shields as Iraqi forces advance on Mosul. (Photo by Felipe Dana/AP Photo)

The main entrance and blast door at the nuclear bunker site on the Woodside Road industrial estate on February 4, 2016 in Ballymena, Northern Ireland. The underground shelter has been put up for sale by the offices of the Northern Ireland First and Deputy First Minister. The bunker which was completed in 1990 was built to hold up to 235 people in the event of a nuclear bomb and is complete with kitchen facilities, dormitories and decontamination chambers. The site, one of approximately 1,600 nuclear monitoring posts built in the UK since 1955, is on the housing market with an asking price of £575,000. (Photo by Charles McQuillan/Getty Images)

Russian participants adjust their hair, preparing for the Kremlin Cadet Ball in Moscow, Russia, 08 December 2016. Pupils of cadet schools from different parts in Russia gathered for the first Kremlin Ball, restoring an old tradition of Russian officers and noble girls. (Photo by Sergei Chirikov/EPA)