In order to add a new column labeled "Region" to your cities data, you can apply this function to each row of the cities dataframe.
import pandas as pd
# Assuming you have a DataFrame named 'cities' with columns 'Latitude' and 'Longitude'
# and you have a function named 'coordinates_to_region'
def coordinates_to_region(latitude, longitude):
# Implement the logic of your coordinates_to_region function
# ...
# Adding a new column 'Region' to the cities DataFrame
cities['Region'] = cities.apply(lambda row: coordinates_to_region(row['Latitude'], row['Longitude']), axis=1)