A paramilitary police officer (right) turns around as hostesses line up for roll call ahead of the Beijing International Automotive Exhibition in Beijing, China, on Monday, April 25, 2016. Tesla Motors Inc. and BYD Co. are among manufacturers showing 147 new-energy vehicles at this year's show. (Photo by Qilai Shen/Bloomberg)

A train attendant helps a passenger to adjust her seat at the business class carriage on a CRH 380A bullet train Thursday, June 16, 2011. (Photo by Reuters/China Daily)

Undated UK Ministry of Defence handout photo of an RAF Tornado GR4 which has been painted in Gulf War “desert pink” paint scheme to honour the aircraft type's almost continuous operational service since the Royal Air Force helped liberate Kuwait from Saddam Hussein's forces, taken by SAC Rose Buchanan, which has been shortlisted for the general public to pick their favourite RAF Image of the Year. (Photo by SAC Rose Buchanan/MoD Crown Copyright/PA Wire)

Former “The Hills” star Audrina Patridge and her on again, off again boyfriend Corey Bohan get into a huge fight after attending Matthew Morrison's Halloween Party at Hyde Nightclub in West Hollywood, California on October 25, 2014. Audrina and Corey, who recently split up this past summer, seemed to be in great spirits before the party started but afterwards it was a whole different story! The not so happy couple argued on a bench and at one point a visibly upset Audrina sat on the sidewalk crying! (Photo by FameFlynet)

“A ball girl is an individual who retrieves balls for players or officials in a variety of sports including association football, American football, tennis, baseball and basketball”. – Wikipedia

Photo: A ball girl runs with 2 balls for Ivo Karlovic of Croatia against Fernando Verdasco of Spain in their second round match during the Mutua Madrilena Madrid Open tennis tournament at the Caja Magica on on May 11, 2010 in Madrid, Spain. (Photo by Clive Brunskill/Getty Images)

In this artist's impression supplied by the ESO (European Southern Observatory) on April 25, 2007, the planetary system around the red dwarf, Gliese 581, is pictured showing what astronomers believe is the most earth like planet found outside our solar system to date. Using the ESO 3.6-m telescope in Chile, astronomers have uncovered the planet which could have water running on its surface. The planet orbits the faint star Gliese 581, which is 20.5 light-years away in the constellation Libra. (Photo by ESO via Getty Images)

In this May 4, 2014 photo, a miner holds an amalgam of mercury and gold he mined after working a 28-hour shift at an illegal gold mining process, in La Pampa, in Peru's Madre de Dios region. Thousands of artisanal gold miners sweat through the long shifts and endure, for a few grams of gold, the perils of collapsing earth, limb-crushing machinery and the toxic mercury used to bind gold flecks. (Photo by Rodrigo Abd/AP Photo)

An enterprising Chinese man pulls a bicycle cart packed high with bags of recyclable plastic containers in Shanghai July 25, 2002. The man sells each kilogram (2.2 pounds) of plastic for 0.08 yuan ($.01) to a nearby depot. (Photo by Claro Cortes IV/Reuters)