1b = bytearray(30)
2f = open("io/data/file1", "rb")
3print(f.readinto(b))
4print(b)
5f = open("io/data/file2", "rb")
6print(f.readinto(b))
7print(b)
8
9# readinto() on writable file
10f = open("io/data/file1", "ab")
11try:
12    f.readinto(bytearray(4))
13except OSError:
14    print("OSError")
15