gistfile1.txt

# Accepts array like [["iPod nano", ["Paris", "France", "Europe"]],
#                     ["Samsung S8", ["London", "UK", "Europe"]],
#                     ["Google Pixal", ["Rio", "Brazil", "South America"]]
#                    ]

from collections import defaultdict

def f(input):
   d = defaultdict(set)
   for obj in input:
       product = obj[0]
       locations = obj[1]
       for loc in locations:
           d[loc].add(product)
   return d