Turn a bunch of cities to its belonging countries
We have around 200k rows of people birth places data. We want to convert those place names to its country level.
The birth places data is a bit messy. We need to clean it a bit.
e.g. France -> France Paris -> France (despite there are a lot of Paris on the planet, we will use the city with the highest population)
French -> France Londoner -> London -> England -> UK
MD -> Maryland -> US