Last year, an Iranian economist named Mohammad Mehdi Behkish was extremely optimistic about prospects for a nuclear deal that would end many economic sanctions on his country.
"Personally, I would say it can't be that there would not be a deal," he told me when I met him in Tehran.
The alternative, he said, was disaster.
Behkish leads Iran's International Chamber of Commerce. When I met him again this month in his Tehran office, he sounded even more optimistic.