如何在单个列表中合并列表值？

list1 = [1, 2, 3]
list2 = [4, 5, 6]
list3 = [7, 8, 9]

merged_list = []
for lst in [list1, list2, list3]:
    merged_list.extend(lst)

print(merged_list)

list1 = [1, 2, 3]
list2 = [4, 5, 6]
list3 = [7, 8, 9]

merged_list = [item for lst in [list1, list2, list3] for item in lst]

print(merged_list)