list.extend and list comprehension

Question

When I need to add several identical items to the list I use list.extend:

a = [\'a\', \'b\', \'c\']
a.extend([\'d\']*3)

Result

Answer 1

>>> a = [['a',2], ['b',2], ['c',1]]
>>> [i for i, n in a for k in range(n)]
['a', 'a', 'b', 'b', 'c']