Python Lambda TypeError I don't know why.

files = input().split()

print(list(lambda a : '{0:0>7}'.format(a) if len(a) == 5 else '{0:0>8}'.format(a), files))

When I type 4.png, I want to print it out as "004.png" Line 2 keeps getting an error below. I don't know what's wrong with Google it(Crying)

An exception has occurred. TypeError list expected at most 1 arguments, got 2