def sum_city_pop():
    '''sum the populations of cities stored in a text file'''
    file = open('population.txt')
    
    # total population
    totalpop = 0
    
    for line in file:
        line = line.strip()
        fields = line.split()
        cityname = fields[0]  # unused here
        citypop = fields[1] # the field we want
        
        totalpop += int(citypop)
        
    print('Total population is', totalpop)
    
    file.close()


def remove_list_duplicates(some_list):
    '''returns a new list that has all the duplicates removed'''
    return list(set(some_list))