LHS slice and the RHS may each be of any length : Slice « List « Python Tutorial

1. Python Tutorial
2. List
3. Slice

x = [1, 2, 3, 4]
x[1:3] = [22, 33, 44]     # x is now [1, 22, 33, 44, 4]
print x
x[1:4] = [8, 9]           # x is now [1, 8, 9, 4]
print x