A worker of the Jumia company pushes a trolley cart between shelves in the warehouse in Lagos, Nigeria January 20, 2020. Picture taken January 20, 2020. REUTERS/Temilade Adelaja

A Techi Linen Cart, a robot manufactured by Techmetics to provide autonomous delivery of laundry, linen and bulky items in hotels, approaches a trolley along a corridor at the housekeeping section of Sofitel Singapore City Centre in Singapore January 31, 2019. Picture taken January 31, 2019. REUTERS/Loriene Perera

A Techi Linen Cart, a service robot manufactured by Techmetics to provide autonomous delivery of laundry, linen and bulky items in hotels, pushes a trolley as it moves along a corridor at the housekeeping section of Sofitel Singapore City Centre in Singapore January 31, 2019. Picture taken January 31, 2019. REUTERS/Loriene Perera

A street vendor cooks corn in an aluminium pot over a fire in Durban, South Africa, August 3, 2018. REUTERS/Rogan Ward

A street vendor cooks corn in an aluminium pot over a fire in Durban, South Africa, August 3, 2018. REUTERS/Rogan Ward

A trolley with bananas is parked on a side of the road at Mbare township outside the capital Harare, Zimbabwe, July 31, 2018. REUTERS/Siphiwe Sibeko

A trolley splashes water during heavy rain in central Minsk, Belarus, July 13, 2018. REUTERS/Vasily Fedosenko

Towels on trolleys are seen in the laundry room at the Radisson Blu Resort and Spa Golden Sands at Golden Bay outside Mellieha, Malta April 13, 2018. REUTERS/Darrin Zammit Lupi

People push a shopping cart carrying firewood over a snow bank during Storm Grayson in Boston, Massachusetts, U.S., January 4, 2018. REUTERS/Brian Snyder

A shopping cart with meat is seen at the Central Market in downtown Lima, Peru, July 25, 2017. REUTERS/Mariana Bazo

Boxes of documents arrive at the Supreme Court on the last day of the challenge against a court ruling that Theresa May's government requires parliamentary approval to start the process of leaving the European Union, in Parliament Square, central London, Britain December 8, 2016. REUTERS/Peter Nicholls

A man pushes passengers on a makeshift trolley in an area where, according to local residents, several people have been killed in police operations since the beginning of country's war on drugs, in Manila, Philippines November 2, 2016. REUTERS/Damir Sagolj

A man pushes people on a makeshift trolley in an area where, according to local residents, several people have been killed in police operations since the beginning of country's war on drugs, in Manila, Philippines November 2, 2016. REUTERS/Damir Sagolj

A boy stands on a railroad track as a man pushes passengers on a makeshift trolley in an area where, according to local residents, several people have been killed in police operations since the beginning of country's war on drugs, in Manila, Philippines November 2, 2016. REUTERS/Damir Sagolj

Shopping trolleys are parked at a Morrisons supermarket in south London, Britain, August 19, 2016. REUTERS/Peter Nicholls/File Photo

A customer pushes a shopping cart past packs of bottled water at a Metro cash and carry store in Kiev, Ukraine, August 17, 2016. REUTERS/Valentyn Ogirenko

Customers shop at a Metro cash and carry store in Kiev, Ukraine, August 17, 2016. REUTERS/Valentyn Ogirenko

Customers shop at a Metro cash and carry store in Kiev, Ukraine, August 17, 2016. REUTERS/Valentyn Ogirenko

A couple buys a pack of bottled water at a Metro cash and carry store in Kiev, Ukraine, August 17, 2016. REUTERS/Valentyn Ogirenko

A customer pushes a shopping cart past shelves stocked with cheese at a Metro cash and carry store in Kiev, Ukraine, August 17, 2016. REUTERS/Valentyn Ogirenko

A customer shops at a Metro cash and carry store in Kiev, Ukraine, August 17, 2016. REUTERS/Valentyn Ogirenko

A woman speaks on her mobile phone while she shops at a Metro cash and carry store in Kiev, Ukraine, August 17, 2016. REUTERS/Valentyn Ogirenko

Customers visit the dairy department of a Metro cash and carry store in Kiev, Ukraine, August 17, 2016. REUTERS/Valentyn Ogirenko

A customer visits the dairy department of a Metro cash and carry store in Kiev, Ukraine, August 17, 2016. REUTERS/Valentyn Ogirenko

A customer pushes a shopping cart past shelves stocked with candies at a Metro cash and carry store in Kiev, Ukraine, August 17, 2016. REUTERS/Valentyn Ogirenko

Shopping carts of German retailer Metro are lined up outside its cash and carry store in Kiev, Ukraine, August 17, 2016. REUTERS/Valentyn Ogirenko

Shopping carts of German retailer Metro are lined up outside its cash and carry store in Kiev, Ukraine, August 17, 2016. REUTERS/Valentyn Ogirenko

A shopping cart is picured in front of a Metro cash and carry store in Kiev, Ukraine, August 17, 2016. REUTERS/Valentyn Ogirenko

A shopping cart is picured outside a Metro cash and carry store in Kiev, Ukraine, August 17, 2016. REUTERS/Valentyn Ogirenko

A man pushes a trolley cart through a warehouse for an online store, Jumia in Ikeja district, in Nigeria's commercial capital Lagos June 10, 2016.REUTERS/Akintunde Akinleye

A worker pushes a dolly loaded with cases of empty Coca-Cola bottles in Caracas, Venezuela May 24, 2016. REUTERS/Carlos Garcia Rawlins

A worker pushes a dolly loaded with cases of empty Coca-Cola bottles in Caracas, Venezuela May 24, 2016. REUTERS/Carlos Garcia Rawlins

A Costco shopping cart is shown at a Costco Wholesale store in Carlsbad, California September 11, 2013. REUTERS/Mike Blake/File Photo GLOBAL BUSINESS WEEK AHEAD PACKAGE - SEARCH 'BUSINESS WEEK AHEAD MAY 23' FOR ALL IMAGES

Customers stand next to shopping trolleys as they shop in a Carrefour hypermarket in Nice, France, April 6, 2016. REUTERS/Eric Gaillard/File Photo GLOBAL BUSINESS WEEK AHEAD PACKAGE - SEARCH 'BUSINESS WEEK AHEAD MAY 23' FOR ALL IMAGES

A worker carries parcels from a truck as he places them onto a trolley for delivery in central Sydney, Australia, May 18, 2016. REUTERS/David Gray

A delivery worker pulls a trolley loaded with parcels and packages along a footpath in central Sydney, Australia, May 18, 2016. REUTERS/David Gray

Staff push trolleys in the rain outside the international airport in Pyongyang, North Korea May 3, 2016. REUTERS/Damir Sagolj

Railroad workers push a trolley at 'Constitucion' train station in Buenos Aires, Argentina, March 31, 2016. REUTERS/Marcos Brindicci

A man transports a sculpture of Christ covered by a colorful cloth on a trolley cart, ahead of the upcoming Holy Week, in downtown Bogota, Colombia March 17, 2016.REUTERS/John Vizcaino TPX IMAGES OF THE DAY

Shopping carts with logos of German supermarket chain Rewe are pictured at a shopping centre in Hanau, Germany, March 17, 2016 Rewe said it would file a complaint to the higher regional court in Duesseldorf after Economy Minister Sigmar Gabriel on Thursday approved a merger of rivals Edeka and Kaiser's. REUTERS/Kai Pfaffenbach TPX IMAGES OF THE DAY

A scrap dealer lights a cigarette next to a pile of rubbish bags in a street during a strike by garbage collectors from waste management company Limasa, who have been on strike since March 1 against wage cuts, and to demand better working conditions in Malaga, southern Spain, March 10, 2016. REUTERS/Jon Nazca

A migrant pulls a cart with his luggage as he arrives at a makeshift camp on the Greek-Macedonian border, near the village of Idomeni, Greece March 9, 2016. REUTERS/Stoyan Nenov

A migrant pushes a cart with firewood close to a makeshift camp on the Greek-Macedonian border, near the village of Idomeni, Greece March 9, 2016. REUTERS/Stoyan Nenov

French riot police surround migrants who pull a trolley with their belongings during the partial dismantlement of the camp for migrants called the "Jungle", in Calais, France, March 3, 2016. REUTERS/Yves Herman

Cheese maker carries Parmesan cheese moulds at 4 Madonne Caseificio dell'Emilia dairy cooperative in Modena, Italy, February 16, 2016. When Parmesan prices proved too volatile for Italy's strained banks a dairy cooperative near Bologna came up with a novel solution to its funding needs, bonds backed by wheels of cheese. But 4 Madonne Caseificio dell'Emilia remains an exception among small businesses struggling to get long-term funds in Italy, where a credit crunch risks holding back a fragile economic recovery after more than a decade of stagnation. REUTERS/Alessandro Bianchi

A lone carnival reveller strolls along a street during Rosenmontag in Mainz, Germany, February 8, 2016. Many traditional Rose Monday carnival parades were cancellend in the Rhineland due to severe weather warnings. Low-pressure system Ruzica, bringing heavy thunderstorms and high winds is predicted for Monday, according to the weather department. REUTERS/Kai Pfaffenbach

A young migrant pulls a trolley in a muddy field at a camp of makeshift shelters for migrants and asylum-seekers from Iraq, Kurdistan, Iran and Syria, called the Grande Synthe jungle, near Calais, France, February 3, 2016. European Union countries on Wednesday approved a 3 billion euro ($3.32 billion) fund for Turkey to improve living conditions for refugees there in exchange for Ankara ensuring fewer of them migrate on to Europe. REUTERS/Yves Herman

Residents push a lever to fill water containers in Douma, Syria February 3, 2016. REUTERS/Bassam Khabieh

Court documents are wheeled into the Montgomery County Courthouse before comedian Bill Cosby's appearance for a preliminary hearing on sexual assault charges in Norristown, Pennsylvania February 2, 2016. Lawyers for Cosby on Tuesday will urge a Pennsylvania judge to throw out criminal charges of sexual assault against him, arguing that the case violates a prosecutor's decade old agreement not to charge Cosby. Cosby, 78, is set to appear in the criminal court where he was charged in December with the 2004 assault of Andrea Constand, a former women's basketball team manager at Temple University in Philadelphia, Cosby's alma mater. REUTERS/Mark Makela

Court documents are wheeled into the Montgomery County Courthouse before comedian Bill Cosby's appearance for a preliminary hearing on sexual assault charges in Norristown, Pennsylvania February 2, 2016. Lawyers for Cosby on Tuesday will urge a Pennsylvania judge to throw out criminal charges of sexual assault against him, arguing that the case violates a prosecutor's decade old agreement not to charge Cosby. Cosby, 78, is set to appear in the criminal court where he was charged in December with the 2004 assault of Andrea Constand, a former women's basketball team manager at Temple University in Philadelphia, Cosby's alma mater. REUTERS/Mark Makela

Court documents are wheeled into the Montgomery County Courthouse before comedian Bill Cosby's appearance for a preliminary hearing on sexual assault charges in Norristown, Pennsylvania February 2, 2016. Lawyers for Cosby on Tuesday will urge a Pennsylvania judge to throw out criminal charges of sexual assault against him, arguing that the case violates a prosecutor's decade old agreement not to charge Cosby. Cosby, 78, is set to appear in the criminal court where he was charged in December with the 2004 assault of Andrea Constand, a former women's basketball team manager at Temple University in Philadelphia, Cosby's alma mater. REUTERS/Mark Makela

Court documents are wheeled into the Montgomery County Courthouse before comedian Bill Cosby's appearance for a preliminary hearing on sexual assault charges in Norristown, Pennsylvania February 2, 2016. Lawyers for Cosby on Tuesday will urge a Pennsylvania judge to throw out criminal charges of sexual assault against him, arguing that the case violates a prosecutor's decade old agreement not to charge Cosby. Cosby, 78, is set to appear in the criminal court where he was charged in December with the 2004 assault of Andrea Constand, a former women's basketball team manager at Temple University in Philadelphia, Cosby's alma mater. REUTERS/Mark Makela

Court documents are wheeled into the Montgomery County Courthouse before comedian Bill Cosby's appearance for a preliminary hearing on sexual assault charges in Norristown, Pennsylvania February 2, 2016. Lawyers for Cosby on Tuesday will urge a Pennsylvania judge to throw out criminal charges of sexual assault against him, arguing that the case violates a prosecutor's decade old agreement not to charge Cosby. Cosby, 78, is set to appear in the criminal court where he was charged in December with the 2004 assault of Andrea Constand, a former women's basketball team manager at Temple University in Philadelphia, Cosby's alma mater. REUTERS/Mark Makela

Court documents are wheeled into the Montgomery County Courthouse before comedian Bill Cosby's appearance for a preliminary hearing on sexual assault charges in Norristown, Pennsylvania February 2, 2016. Lawyers for Cosby on Tuesday will urge a Pennsylvania judge to throw out criminal charges of sexual assault against him, arguing that the case violates a prosecutor's decade old agreement not to charge Cosby. Cosby, 78, is set to appear in the criminal court where he was charged in December with the 2004 assault of Andrea Constand, a former women's basketball team manager at Temple University in Philadelphia, Cosby's alma mater. REUTERS/Mark Makela

Sheep stand in a supermarket trolley outside a butcher shop in Tadamoun neighbourhood in Tunis, Tunisia February 2, 2016. REUTERS/Zohra Bensemra

A customer pulls a caddy inside a Casino shop in Nice, France, January 14, 2016. French retailer Casino answered criticism from research and investment firm Muddy Waters LLC on Thursday with fourth-quarter sales that beat expectations as a domestic recovery gained momentum, helped by price cuts. REUTERS/Eric Gaillard

A customer chooses a meat product at Sun Art Retail Group's Auchan hypermarket store in Beijing, China, November 9, 2015. REUTERS/Kim Kyung-Hoon

A customer pushes a shopping cart at Sun Art Retail Group's Auchan hypermarket store in Beijing, China, November 9, 2015. REUTERS/Kim Kyung-Hoon

A customer's shopping cart is placed at Sun Art Retail Group's Auchan hypermarket store in Beijing, China, November 9, 2015. REUTERS/Kim Kyung-Hoon

A customer pushes a shopping cart at Sun Art Retail Group's Auchan hypermarket store in Beijing, China, November 9, 2015. REUTERS/Kim Kyung-Hoon