A humanoid robot named “Yangyang” shows a facial expression during its demonstration at the Global Mobile Internet Conference (GMIC) 2015 in Beijing, China, April 29, 20155. The android was produced jointly by China's Shanghai Yangyang Intellegent Robot Science Service center and Japanese professor Hiroshi Ishiguro, with the aim of popularising robotics among the young. (Photo by Kim Kyung-Hoon/Reuters)

In this March 13, 2015 photo, Yohan, 4, from left, Cristian, 7, and Angelo, 6, playfully toss coca leaves into the air, singing: “I have a lot of money, look at all the money I have”, in La Mar, province of Ayacucho, Peru. Hauling cocaine out of the remote valley is about the only way to earn decent cash in this region where a farmhand earns less than $10 a day. Beyond extinguishing young lives, the practice has packed Peru's highland prisons with cocaine backpackers while their bosses evade incarceration. (Photo by Rodrigo Abd/AP Photo)

Revellers take part in the annual “Naval Battle” of Vallecas in Madrid, Spain July 19, 2015. The slogan for this year's water battle is “Get wet for Alfon, freedom for Alfon”, referring to Alfonso Fernandez Ortega, a Vallecas resident who was sentenced to four years in prison in June. The festival was started spontaneously in 1981 when some neighbours started to throw water at one another due to high temperatures during the Virgen del Carmen Festival. (Photo by Juan Medina/Reuters)

An exile Tibetan monk gestures as he makes a point in a dialectics debate with another monk, sitting right, at the Kirti monastery in Dharmsala, India, Monday, January 18, 2016. The debate is an essential part of their training as Buddhist monks. (Photo by Ashwini Bhatia/AP Photo)

A debutante from a local academy looks at her mobile phone as she waits to take part in the Vienna Ball at the Kempinski Hotel, March 19, 2016, in Beijing. The ball, which is an event organized by the luxury Kempinski Hotel chain and the City of Vienna, brings together both Chinese and foreign members of the capital's elite class. Despite a slowing economy, private wealth has soared in China after decades of rapid growth. A record number of high net worth individuals and families has fuelled a market for luxury goods, services, and events catering to China's burgeoning elite class. (Photo by Kevin Frayer/Getty Images)

Dancers wear traditional dresses as they perform during women's dance festival in Jogeva, Estonia, June 12, 2016. (Photo by Ints Kalnins/Reuters)

Satrio smokes at a kiosk after elementary school on March 3, 2017 in Yogyakarta, Indonesia. Satrio has smoked up to one pack a day and began when he was six years old. (Photo by Ulet Ifansasti/Getty Images)

Edibles are displayed at Shango Cannabis shop on first day of legal recreational marijuana sales beginning at midnight in Portland, Oregon October 1, 2015. The sale of marijuana for recreational use began in Oregon on October 1, 2015 as it joined Washington state and Colorado in allowing the sale of a drug that remains illegal under U.S. federal law. (Photo by Steve Dipaola/Reuters)