random to produce duplicated elements

When working with random module

In [1]: from random import *                                                                                                  

In [2]: sample([10, 20, 30, 40, 50], k=4)                                                                                     
Out[2]: [20, 30, 50, 10]

the result is not randomly completely

How could produce a result as

In [2]: sample([10, 20, 30, 40, 50], k=4)                                                                                     
Out[2]: [20, 20, 20, 10]

to generate duplicated elements.