我想这应该能解决你的问题。

import csv

def toSeconds(t):
    return int(t.split(":")[0]) * 60 + int(t.split(":")[1])

def toTime(seconds):
    minutes = seconds // 60
    seconds = seconds % 60
    return str(minutes) + ":" + str(seconds)

with open("time.csv") as timedata:
    total = 0
    for row in csv.reader(timedata):
        for col in row:
            total += toSeconds(col)
    total = toTime(total)