print(bytearray(4))
a = bytearray([1, 2, 200])
print(type(a))
print(a[0], a[2])
print(a[-1])
print(a)
a[2] = 255
a.append(10)
print(len(a))
s = 0
for i in a:
s += i
print(s)
print(a[1:])
print(a[:-1])
print(a[2:3])