import datetime

starttime = datetime.datetime.now()
# long running
# do something other
lls = []
i = 0
for i in range(300000):
    lls.append(i)
    # if len(lls) > 1000:
    #        lls = []
    i = i + 1
    if i > 1000:
        lls = []
        i = 0
endtime = datetime.datetime.now()
print((endtime - starttime))