A man and woman look at tributes outside the house of singer George Michael, where he died on Christmas Day, in Goring, southern England, Britain December 26, 2016. REUTERS/Eddie Keogh 

A man stands by tributes outside the house of singer George Michael, where he died on Christmas Day, in Goring, southern England, Britain December 26, 2016. REUTERS/Eddie Keogh 

A man carries flowers to the house of singer George Michael, where he died on Christmas Day, in Goring, southern England, Britain December 26, 2016. REUTERS/Eddie Keogh 

A man and a woman look at tributes outside the house of singer George Michael, where he died on Christmas Day, in Goring, southern England, Britain December 26, 2016. REUTERS/Eddie Keogh 

Football Soccer - 2017 Copa Libertadores draw - CONMEBOL headquarters, Luque, Paraguay - 21/12/2016 Alejandro Dominguez, president of the South American Football Federation (CONMEBOL), speaks. REUTERS/Jorge Adorno 

Football Soccer - 2017 Copa Libertadores draw - CONMEBOL headquarters, Luque, Paraguay - 21/12/2016 Alejandro Dominguez, president of the South American Football Federation (CONMEBOL), speaks. REUTERS/Jorge Adorno 

A man is seen inside a store in Caracas, Venezuela, December 1, 2016. Picture taken December 1, 2016. REUTERS/Ueslei Marcelino 

A Christian tourist from Nigeria stands during a boat ride in the Sea of Galilee, northern Israel November 30, 2016. REUTERS/Ronen Zvulun SEARCH "GALILEE" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES. 

A man wearing a respiratory protection mask is pictured in the subway after a red alert was issued for heavy air pollution in Beijing, China, December 20, 2016. REUTERS/Jason Lee 

A man wearing a respiratory protection mask is pictured in the subway after a red alert was issued for heavy air pollution in Beijing, China, December 20, 2016. REUTERS/Jason Lee 

A man holds an upside down flag as people protest against U.S. President-elect Donald Trump as electors gather to cast their votes for U.S. president at the Pennsylvania State Capitol in Harrisburg, Pennsylvania, U.S. December 19, 2016. Pennsylvania's twenty electors are assumed to be committed to Trump by virtue of his having won the popular vote in the state, but the vote that is usually routine takes place this year amid allegations of Russian hacking to try to influence the election. REUTERS/Jonathan Ernst 

A man cooks in open air as heavy smog blankets Shengfang, in Hebei province, on an extremely polluted day with red alert issued, China December 19, 2016. REUTERS/Damir Sagolj 

A man with a baby rides a bus to be evacuated from a rebel-held sector of eastern Aleppo, Syria December 18, 2016. Picture taken December 18, 2016. REUTERS/Abdalrhman Ismail 

Displaced Iraqis who fled the Islamic State stronghold of Mosul, walk following heavy rain at Khazer camp, Iraq, December 19, 2016. REUTERS/Ammar Awad 

Ukraine's First Vice Prime Minister and Economy Minister Stepan Kubiv and European Union foreign policy chief Federica Mogherini address a joint news conference during a EU-Ukraine Association Council in Brussels, Belgium December 19, 2016. REUTERS/Francois Lenoir 

Ukraine's First Vice Prime Minister and Economy Minister Stepan Kubiv and European Union foreign policy chief Federica Mogherini attend a EU-Ukraine Association Council in Brussels, December 19, 2016. REUTERS/Francois Lenoir 

European Union foreign policy chief Federica Mogherini poses with Ukraine's First Vice Prime Minister Stepan Kubiv and Vice Prime Minister Ivanna Klympush-Tsintsadze (L) during a EU-Ukraine Association Council in Brussels, December 19, 2016. REUTERS/Francois Lenoir 

Britain Football Soccer - West Bromwich Albion v Manchester United - Premier League - The Hawthorns - 17/12/16 West Bromwich Albion owner Guochuan Lai (L) in the stands Action Images via Reuters / John Sibley Livepic EDITORIAL USE ONLY. No use with unauthorized audio, video, data, fixture lists, club/league logos or "live" services. Online in-match use limited to 45 images, no video emulation. No use in betting, games or single club/league/player publications. Please contact your account representative for further details. 

Britain Football Soccer - West Bromwich Albion v Manchester United - Premier League - The Hawthorns - 17/12/16 West Bromwich Albion owner Guochuan Lai (L) in the stands Action Images via Reuters / John Sibley Livepic EDITORIAL USE ONLY. No use with unauthorized audio, video, data, fixture lists, club/league logos or "live" services. Online in-match use limited to 45 images, no video emulation. No use in betting, games or single club/league/player publications. Please contact your account representative for further details. 

North Rhine Westphalia (NRW) AfD party leader Marcus Pretzell and German anti-immigration party Alternative for Germany (AfD) leader Frauke Petry (R) address a news conference in Berlin, Germany, December 16, 2016. REUTERS/Fabrizio Bensch 

North Rhine Westphalia (NRW) AfD party leader Marcus Pretzell and German anti-immigration party Alternative for Germany (AfD) leader Frauke Petry (R) address a news conference in Berlin, Germany, December 16, 2016. REUTERS/Fabrizio Bensch 

North Rhine Westphalia (NRW) AfD party leader Marcus Pretzell and German anti-immigration party Alternative for Germany (AfD) leader Frauke Petry (R) address a news conference in Berlin, Germany, December 16, 2016. REUTERS/Fabrizio Bensch 

North Rhine Westphalia (NRW) AfD party leader Marcus Pretzell and German anti-immigration party Alternative for Germany (AfD) leader Frauke Petry (R) address a news conference in Berlin, Germany, December 16, 2016. REUTERS/Fabrizio Bensch 

North Rhine Westphalia (NRW) AfD party leader Marcus Pretzell and German anti-immigration party Alternative for Germany (AfD) leader Frauke Petry (R) address a news conference in Berlin, Germany, December 16, 2016. REUTERS/Fabrizio Bensch 

North Rhine Westphalia (NRW) AfD party leader Marcus Pretzell and German anti-immigration party Alternative for Germany (AfD) leader Frauke Petry (R) address a news conference in Berlin, Germany, December 16, 2016. REUTERS/Fabrizio Bensch 

North Rhine Westphalia AfD party leader Marcus Pretzell talks to German AfD leader Frauke Petry (R) before a news conference of the anti-immigration party Alternative for Germany (AfD) in Berlin, Germany, December 16, 2016. REUTERS/Fabrizio Bensch 

North Rhine Westphalia AfD party leader Marcus Pretzell before a news conference of the anti-immigration party Alternative for Germany (AfD) in Berlin, Germany, December 16, 2016. REUTERS/Fabrizio Bensch 

Francois De Rugy, former co-president of the ecologist group at the National Assembly and candidate for January's Socialist presidential primary, attends a debate about ecological issues in Paris, France, December 15, 2016. REUTERS/Christian Hartmann

Francois De Rugy, former co-president of the ecologist group at the National Assembly and candidate for January's Socialist presidential primary, attends a debate about ecological issues in Paris, France, December 15, 2016. REUTERS/Christian Hartmann

Francois De Rugy, former co-president of the ecologist group at the National Assembly and candidate for January's Socialist presidential primary, attends a debate about ecological issues in Paris, France, December 15, 2016. REUTERS/Christian Hartmann

Francois De Rugy, former co-president of the ecologist group at the National Assembly and candidate for January's Socialist presidential primary, attends a debate about ecological issues in Paris, France, December 15, 2016. REUTERS/Christian Hartmann

Mohammad Hassan, whose hand was chopped off by Islamic State militants, sits outside a house at Nimrud village, south of Mosul, Iraq, December 13, 2016. Picture taken December 13, 2016. REUTERS/Mohammed Salem 

Mohammad Hassan, whose hand was chopped off by Islamic State militants, sits next to his aunt in a house at Nimrud village, south of Mosul, Iraq, December 13, 2016. Picture taken December 13, 2016. REUTERS/Mohammed Salem 

Azad Hassan (R) and his brother Mohammad, whose hands were chopped off by Islamic State militants, sit with their aunt n a house at Nimrud village, south of Mosul, Iraq, December 13, 2016. Picture taken December 13, 2016. REUTERS/Mohammed Salem 

A girl looks on as Mohammad Hassan, whose hand was chopped off by Islamic State militants, stands in a house at Nimrud village, south of Mosul, Iraq, December 13, 2016. Picture taken December 13, 2016. REUTERS/Mohammed Salem 

Mohammad Hassan, whose hand was chopped off by Islamic State militants, holds his daughter in a house at Nimrud village, south of Mosul, Iraq, December 13, 2016. Picture taken December 13, 2016. REUTERS/Mohammed Salem 

Mohammad Hassan, whose hand was chopped off by Islamic State militants, stands next to his wife in a house at Nimrud village, south of Mosul, Iraq, December 13, 2016. Picture taken December 13, 2016. REUTERS/Mohammed Salem 

Azad Hassan (R) and his brother Mohammad, whose hands were chopped off by Islamic State militants, sit next to each other at Nimrud village, south of Mosul, Iraq, December 13, 2016. Picture taken December 13, 2016. REUTERS/Mohammed Salem TPX IMAGES OF THE DAY 

Mohammad Hassan (R), whose hand was chopped off by Islamic State militants, stands next to his wife as he plays with his daughter in a house at Nimrud village, south of Mosul, Iraq, December 13, 2016. Picture taken December 13, 2016. REUTERS/Mohammed Salem 

Mohammad Hassan, whose hand was chopped off by Islamic State militants, poses for a picture in a house at Nimrud village, south of Mosul, Iraq, December 13, 2016. Picture taken December 13, 2016. REUTERS/Mohammed Salem 

Mohammad Hassan, whose hand was chopped off by Islamic State militants, warms himself in a house at Nimrud village, south of Mosul, Iraq, December 13, 2016. Picture taken December 13, 2016. REUTERS/Mohammed Salem 

A man sits on a log on a cold winter morning in Srinagar, December 15, 2016. REUTERS/Danish Ismail 

Seijiro Katsura, a 44-year-old office worker, checks market rates for investment opportunities using his laptop computer at his home in Tokyo, Japan December 10, 2016. Picture taken December 10, 2016. REUTERS/Issei Kato 

Seijiro Katsura, a 44-year-old office worker, checks market rates for investment opportunities using his smart phone at his home in Tokyo, Japan December 10, 2016. Picture taken December 10, 2016. REUTERS/Issei Kato 

Seijiro Katsura, a 44-year-old office worker, checks market rates for investment opportunities using his smart phone at his home in Tokyo, Japan December 10, 2016. Picture taken December 10, 2016. REUTERS/Issei Kato 

Seijiro Katsura, a 44-year-old office worker, checks market rates for investment opportunities using his laptop computer at his home in Tokyo, Japan December 10, 2016. Picture taken December 10, 2016. REUTERS/Issei Kato 

CEO at Tesla Elon Musk enters Trump Tower ahead of a meeting of technology leaders with President-elect Donald Trump in Manhattan, New York City, U.S., December 14, 2016. REUTERS/Andrew Kelly 

CEO at Tesla Elon Musk enters Trump Tower ahead of a meeting of technology leaders with President-elect Donald Trump in Manhattan, New York City, U.S., December 14, 2016. REUTERS/Andrew Kelly 

French politician Arnaud Montebourg, candidate for January's Socialist presidential primary, visits a camp for migrants in Grande Synthe, France December 14, 2016. REUTERS/Pascal Rossignol 

French politician Arnaud Montebourg, candidate for January's Socialist presidential primary, visits a camp for migrants in Grande Synthe, France December 14, 2016. REUTERS/Pascal Rossignol 

French politician Arnaud Montebourg, candidate for January's Socialist presidential primary, visits a camp for migrants in Grande Synthe, France December 14, 2016. REUTERS/Pascal Rossignol 

Opposition People's Party lawmaker Lee Yong-joo shows impeached President Park Geun-hye's three pictures combo each taken on May 9th, May 13th, May 19, 2014 respectively, during a hearing at the National Assembly in Seoul, South Korea December 14, 2016. The letters read "Is Park's bruise on her face (circled on photos) due to cosmetic filler?". REUTERS/Ahn Young-joon/Pool 

Kim Young-jae, who heads a hospital regularly visited by impeached President Park Geun-hye's longtime friend Choi Soon-sil, speaks during a hearing at the National Assembly in Seoul, South Korea December 14, 2016. REUTERS/Ahn Young-joon/Pool 

(L-R) Kim Won-ho, Suh Chang-suk and Lee Byung-seok, the former chiefs of the presidential house medical team, attend a hearing at the National Assembly in Seoul, South Korea December 14, 2016. REUTERS/Ahn Young-joon/Pool 

Stephen Bannon, Senior Advisor to U.S. President-elect Donald Trump (R) and Reince Priebus stand as U.S. President-elect Donald Trump speaks at the USA Thank You Tour event at the Wisconsin State Fair Exposition Center in West Allis, Wisconsin, U.S., December 13, 2016. REUTERS/Shannon Stapleton TPX IMAGES OF THE DAY 

Stephen Bannon, Senior Advisor to U.S. President-elect Donald Trump (R) and Reince Priebus stand as U.S. President-elect Donald Trump speaks at the USA Thank You Tour event at the Wisconsin State Fair Exposition Center in West Allis, Wisconsin, U.S., December 13, 2016. REUTERS/Shannon Stapleton 

A man pushes a cart with belongings as he flees deeper with another man into the remaining rebel-held areas of Aleppo, Syria December 13, 2016. REUTERS/Abdalrhman Ismail 

French Prime Minister Bernard Cazeneuve (R) speaks with housing minister Emmanuelle Cosse (C) next to Minister for Ecology, Sustainable Development and Energy Segolene Royal (L) before a speech outlining his new government program at the National Assembly in Paris, France, December 13, 2016. REUTERS/Philippe Wojazer

Francois De Rugy, former co-president of the ecologist group at the National Assembly, attends the start of the Socialist Party's "Universite d'ete" summer meeting in La Rochelle, France, August 28, 2015. REUTERS/Stephane Mahe 

Francois De Rugy, former co-president of the ecologist group at the National Assembly, attends the start of the Socialist Party's "Universite d'ete" summer meeting in La Rochelle, France, August 28, 2015. REUTERS/Stephane Mahe