Вы имеете в виду это?
message = [1, 7, {3: "tsdf", "y": (4, 7)}, [4, 8, 'w']]
def print_fields(message):
if type(message) not in (list, tuple, dict, set):
return
for i in message:
if type(i) in (list, tuple, dict, set):
print_fields(i)
else:
print(i)
# -> 1, 7, 3, 'y', 4, 8, 'w'