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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def load_cities(self, filename):
 """ Load up all cities in lowercase for easier matching. The file should have one city per line, with no extra characters. This isn't strictly required, but will vastly increase the accuracy. """

        with open(filename, 'r') as f:
            for line in f:
                self.cities.append(line.strip().lower())