U.S. Senator Cory Booker wipes perspiration as he speaks at his Hometown Kickoff event, part of the senator's "Justice for All" tour, the first such national tour of his presidential campaign in Newark, New Jersey, U.S., April 13, 2019. REUTERS/Andrew Kelly TPX IMAGES OF THE DAY

U.S. Senator Cory Booker wipes perspiration as he speaks at his Hometown Kickoff event, part of the senator's "Justice for All" tour, the first such national tour of his presidential campaign in Newark, New Jersey, U.S., April 13, 2019. REUTERS/Andrew Kelly

U.S. Senator Cory Booker wipes perspiration as he speaks at his Hometown Kickoff event, part of the senator's "Justice for All" tour, the first such national tour of his presidential campaign in Newark, New Jersey, U.S., April 13, 2019. REUTERS/Andrew Kelly

Acting U.S.Attorney General Matthew Whitaker wipes perspiration as he addresses a news conference to announce indictments against China's Huawei Technologies Co Ltd, several of its subsidiaries and its chief financial officer Meng Wanzhou, in a pair of cases accusing the company of everything from bank and wire fraud to obstructing justice and conspiring to steal trade secrets from T-Mobile US Inc., at the Justice Department in Washington, U.S., January 28, 2019. REUTERS/Joshua Roberts TPX IMAGES OF THE DAY

Acting U.S.Attorney General Matthew Whitaker wipes perspiration as he addresses a news conference to announce indictments against China's Huawei Technologies Co Ltd, several of its subsidiaries and its chief financial officer Meng Wanzhou, in a pair of cases accusing the company of everything from bank and wire fraud to obstructing justice and conspiring to steal trade secrets from T-Mobile US Inc., at the Justice Department in Washington, U.S., January 28, 2019. REUTERS/Joshua Roberts

Baseball - 2018 Asian Games - Men's Team Gold Medal Match - South Korea vs Japan - GBK Baseball Field - Jakarta, Indonesia - September 1, 2018. Ryoga Tomiyama of Japan wipes his perspiration. REUTERS/Issei Kato

Baseball - 2018 Asian Games - Men's Team Gold Medal Match - South Korea vs Japan - GBK Baseball Field - Jakarta, Indonesia - September 1, 2018. Japan's starting pitcher Ryoga Tomiyama (C) wipes his perspiration during first inning. REUTERS/Issei Kato

A Rohingya refugee perspires while waiting to receive aid in Cox's Bazar, Bangladesh, September 27, 2017. REUTERS/Cathal McNaughton TPX IMAGES OF THE DAY

A Rohingya refugee perspires while waiting to receive aid in Cox's Bazar, Bangladesh, September 27, 2017. REUTERS/Cathal McNaughton

An anti-riot police officer perspires as he blocks people, who are demonstrating against U.S., Japan, China and the Association of Southeast Asian Nations (ASEAN), ahead of the ASEAN summit in Manila, Philippines April 28, 2017. REUTERS/Erik De Castro

U.S. President Barack Obama mops the sweat from his brow after delivering remarks at a North Carolina Democratic Party "Get Out the Early Vote' campaign event for Hillary Clinton at the University of North Carolina at Chapel Hill, North Carolina, U.S. November 2, 2016. REUTERS/Jonathan Ernst

Tennis - China Open Men's Singles quarterfinal - Beijing, China - 07/10/16. Sweat drips from Rafael Nadal of Spain as he plays against Grigor Dimitrov of Bulgaria. REUTERS/Thomas Peter

Tennis - China Open Men's Singles quarterfinal - Beijing, China - 07/10/16. Sweat drips from Rafael Nadal of Spain as he plays against Grigor Dimitrov of Bulgaria. REUTERS/Thomas Peter TPX IMAGES OF THE DAY

Tennis - China Open men's singles second Round - Beijing, China - 06/10/16. Sweat drips off the face of Rafael Nadal of Spain as he plays against Adrian Mannarino of France. REUTERS/Thomas Peter

Yuan Yunping wipes sweat from his face as he eats dinner, which his son cooked for him, in his room at the accommodation where some patients and their family members stay while seeking medical treatment in Beijing, China, January 13, 2016. Yuan, who suffers from melanoma, came from Hebei Province to seek specialist treatment in Beijing. REUTERS/Kim Kyung-Hoon SEARCH "HOSPITAL ACCOMMODATION" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES.

Formula One - Singapore Grand Prix - Marina Bay, Singapore - 16/9/16 Mercedes' Lewis Hamilton of Britain wipes his perspiration during first practice. REUTERS/Edgar Su

U.S. House Speaker Paul Ryan (R-WI) (L) wipes the sweat from his brow as he and Republican vice presidential nominee Mike Pence hold a joint news conference following a House Republican party conference meeting in Washington, U.S. September 13, 2016. REUTERS/Jonathan Ernst

U.S. House Speaker Paul Ryan (R-WI) (L) wipes the sweat from his brow as he and Republican vice presidential nominee Mike Pence hold a joint news conference following a House Republican party conference meeting in Washington, U.S. September 13, 2016. REUTERS/Jonathan Ernst TPX IMAGES OF THE DAY

U.S. President Barack Obama wipes the sweat from his face as he greets homeowners during a tour of a flood-affected neighborhood in Zachary, Louisiana, U.S., August 23, 2016. REUTERS/Jonathan Ernst

U.S. President Barack Obama wipes the sweat from his face as he greets homeowners during a tour of a flood-affected neighborhood in Zachary, Louisiana, U.S., August 23, 2016. REUTERS/Jonathan Ernst

U.S. President Barack Obama wipes the sweat from his face as he greets homeowners during a tour of a flood-affected neighborhood in Zachary, Louisiana, U.S., August 23, 2016. REUTERS/Jonathan Ernst

Football Soccer - Portugal v Wales - EURO 2016 - Semi Final - Stade de Lyon, Lyon, France - 6/7/16
Portugal's Cristiano Ronaldo
REUTERS/Darren Staples
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Tennis - Italy Open - Rafael Nadal of Spain v Philipp Kohlschreiber of Germany - Rome, Italy - 11/5/16 Nadal serves. REUTERS/Stefano Rellandini

Presidential candidate Rodrigo "Digong" Duterte wipes perspiration on his face beside an aide during election campaigning in Malabon, Metro Manila in the Philippines April 27, 2016. REUTERS/Erik De Castro

Presidential candidate Rodrigo "Digong" Duterte wipes perspiration on his face beside an aide during election campaigning in Malabon, Metro Manila in the Philippines April 27, 2016. REUTERS/Erik De Castro

Tennis - Madrid Open - Rafael Nadal of Spain v Andrey Kuznetsov of Russia - Madrid, Spain - 3/5/16 Drops of sweat fall from Nadal's face. REUTERS/Sergio Perez

Presidential candidate Grace Poe uses her arm to wipe perspiration from her eyes during election campaigning in Dasmarinas, Cavite in the Philippines May 3, 2016. REUTERS/Erik De Castro

Boxing - Kohei Kono of Japan v Inthanon Sithchamuang of Thailand - WBA super-flyweight title - Ota City General Gymnasium, Tokyo, Japan - 27/4/16. Kohei Kono of Japan in actiion with Inthanon Sithchamuang of Thailand. REUTERS/Issei Kato TPX IMAGES OF THE DAY

Tennis - Monte Carlo Masters - Monaco, 13/04/2016. A drop of sweat falls from the face of Rafael Nadal of Spain during his match against Aljaz Bedene of Britain. REUTERS/Eric Gaillard

Andreas Vosskuhle (R ) President of Germany's Constitutional Court and judge Peter Mueller preside over trial against the Nationaldemokratische Partei Deutschlands (NPD) in Karlsruhe, Germany, March 1, 2016. Germany's highest court opened proceedings on Tuesday on whether to ban the far-right NPD, increasing the likelihood that the party branded by critics as neo-Nazi could soon be outlawed. REUTERS/Kai Pfaffenbach

Football Soccer - Wolverhampton Wanderers v Bolton Wanderers - Sky Bet Football League Championship - Molineux - 15/16 - 2/2/16
Bolton Wanderers' Liam Trotter looks dejected
Mandatory Credit: Action Images / Craig Brough

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Maxim Kovtun of Russia reacts after the men's free program at the ISU European Figure Skating Championship in Bratislava, Slovakia, January 28, 2016. REUTERS/David W Cerny

Football Soccer - Barcelona v Athletic Bilbao - Spanish King's Cup - Camp Nou stadium, Barcelona - 27/1/16Barcelona's Ivan Rakitic gestures while Athletic Bilbao's players celebrate a goal. REUTERS/Albert Gea

Sweats flies off the hand of Britain's Andy Murray as he hits a shot during his quarter-final match against Spain's David Ferrer at the Australian Open tennis tournament at Melbourne Park, Australia, January 27, 2016. REUTERS/Thomas Peter

Britain's Andy Murray reacts during a practice session at the Australian Open tennis tournament at Melbourne Park, Australia, January 24, 2016. REUTERS/Jason Reed

Sweat drips from the nose of Spain's Rafael Nadal during his first round match against Spain's Fernando Verdasco at the Australian Open tennis tournament at Melbourne Park, Australia, January 19, 2016. REUTERS/Thomas Peter

Sweat drips from the nose of Spain's Rafael Nadal during his first round match against Spain's Fernando Verdasco at the Australian Open tennis tournament at Melbourne Park, Australia, January 19, 2016. REUTERS/Thomas Peter

Sebastien Loeb of France wipes sweat off his face inside his Peugeot at the end of the Villa Carlos Paz-Termas de Rio Hondo second stage in the Dakar Rally 2016 in Cordoba province, Argentina, January 4, 2016. REUTERS/Marcos Brindicci

Football Soccer - Leicester City v Chelsea - Barclays Premier League - King Power Stadium - 14/12/15
Leicester's Jamie Vardy
Reuters / Andrew Yates
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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.

U.S. Democratic presidential candidate Bernie Sanders wipes the sweat off his face during a campaign rally at Cornell College in Mount Vernon, Iowa December 13, 2015. REUTERS/Mark Kauzlarich

Ma'a Nonu of New Zealand is tackled during their Rugby World Cup Semi-Final match against South Africa at Twickenham in London, Britain, October 24, 2015. REUTERS/Stefan Wermuth

A dancer checks her positioning while rehearsing for the Rockettes 2015 Radio City Christmas Spectacular in New York October 15, 2015. REUTERS/Lucas Jackson TPX IMAGES OF THE DAY

Ali Rezaian, brother of imprisoned Washington Post journalist Jason Rezaian, wipes his brow as he talks about the recent announcement of a verdict in his brother's case by Iran's judiciary during an interview with Reuters in Washington October 13, 2015. REUTERS/Jim Bourg

U.S. Senator Bernie Sanders (I-VT), Democratic presidential candidate, wipes sweat from his forehead as he delivers remarks at a Congressional Hispanic Caucus Institute presidential candidates forum in Washington, October 7, 2015. REUTERS/Jonathan Ernst

Rafael Nadal of Spain prepares to serve against Wu Di of China during their men's singles match at the China Open tennis tournament in Beijing, China, October 6, 2015. REUTERS/Kim Kyung-Hoon

India’s Congress party president Sonia Gandhi wipes her sweat as party’s vice-president Rahul Gandhi (L) watches during a farmers rally at Ramlila ground in New Delhi, India, September 20, 2015. REUTERS/Adnan Abidi

Switzerland's Roger Federer reacts during his Group play-off tennis match against Theimo de Bakker of the Netherlands at the Palexpo Arena in Geneva, Switzerland September 20, 2015. REUTERS/Denis Balibouse

Trey Songz wipes away sweat with his shirt as he performs during the second night of the 2015 iHeartRadio Music Festival at the MGM Grand Garden Arena in Las Vegas, Nevada September 19, 2015. REUTERS/Steve Marcus

Novak Djokovic of Serbia reacts between games against Roger Federer of Switzerland in the third set during their men's singles final match at the U.S. Open Championships tennis tournament in New York, September 13, 2015. REUTERS/Lucas Jackson

Novak Djokovic of Serbia reacts between games against Roger Federer of Switzerland in the third set during their men's singles final match at the U.S. Open Championships tennis tournament in New York, September 13, 2015. REUTERS/Lucas Jackson

Novak Djokovic of Serbia towels off in the third set against Roger Federer of Switzerland during their men's singles final match at the U.S. Open Championships tennis tournament in New York, September 13, 2015. REUTERS/Mike Segar

Marin Cilic of Croatia wipes some sweat away from his forehead as he plays Novak Djokovic of Serbia during their men's singles semi-final match at the U.S. Open Championships tennis tournament in New York, September 11, 2015. REUTERS/Mike Segar

Sweat drips off the nose of Richard Gasquet of France as he faces Roger Federer of Switzerland in their quarterfinals match at the U.S. Open Championships tennis tournament in New York, September 9, 2015. REUTERS/Carlo Allegri

Serena Williams of the U.S. wipes perspiration off her forehead as she plays against her sister and compatriot Venus Williams during their quarterfinals match at the U.S. Open Championships tennis tournament in New York, September 8, 2015. REUTERS/Carlo Allegri

John Isner of the U.S. perspires during his fourth round match against Roger Federer of Switzerland at the U.S. Open Championships tennis tournament in New York September 7, 2015. REUTERS/Eduardo Munoz

Novak Djokovic of Serbia wipes his face after returning a shot to Roberto Bautista Agut of Spain during their fourth round match at the U.S. Open tennis tournament in New York, September 6, 2015. REUTERS/Eduardo Munoz

Serbia's Novak Djokovic wipes his face after returning a shot to Spain's Roberto Bautista Agut during their fourth round match at the U.S. Open Championships tennis tournament in New York September 6, 2015. REUTERS/Eduardo Munoz

Kiki Bertens of the Netherlands wipes down between games in her second round match against Serena Williams of the U.S. at the U.S. Open Championships tennis tournament in New York, September 2, 2015. REUTERS/Carlo Allegri

Roger Federer of Switzerland wipes his brow during his match with Leonardo Mayer of Argentina in the first round at the U.S. Open Championships tennis tournament in New York, September 1, 2015. REUTERS/Brendan McDermid

Roger Federer of Switzerland wipes the sweat from his face during a break in play against Leonardo Mayer from Argentina during their first round match at the U.S. Open Championships tennis tournament in New York, September 1, 2015. REUTERS/Carlo Allegri