import csv
data = {"раздел1": ["запись1", "запись2", "запись3"]}
with open('test.csv', 'w', newline='') as csvfile:
spamwriter = csv.writer(csvfile, delimiter=',',
quotechar='"', quoting=csv.QUOTE_MINIMAL)
for k, v in data.items():
spamwriter.writerow((k,v[0]))
if len(v)>1:
for entry in v[1:]:
spamwriter.writerow(("",entry))
只需在第一列中输入一个空值。例子: