ISTANBUL, TURKEY - NOVEMBER 27:  A man sells chestnuts in front of a branch of the Turkish Halk Bank on November 27, 2017 in Istanbul, Turkey. The trial of Mr. Reza Zarrab an Iranian-Turk who ran a foreign exchange and gold dealership got under way in New York today. Mr Zarrab is accused of managing a billion-dollar scheme to smuggle gold for Iranian oil and conspiring to violate United States sanctions against Iran. Should Mr Zarrab testify, the United States could take action against Turkish banks and government officials found to have been involved in the scheme.  (Photo by Chris McGrath/Getty Images)