aggregation

#!/usr/bin/env python3


data = {}


def main():
    FILENAME = 'foo.csv'

    with open(FILENAME, 'r') as f:
        for line in f.readlines():
            line = line.strip()
            line = line.split(',')
            aggregate(line)
    print(data)



def aggregate(line):
    key = line[0]
    value = line[1]

    if key in data:
        data[key] += value
    else:
        data[key] = value

if __name__ == "__main__":
    main()