{{{id=1|
# replace /home/tom/maths/free_sigma/ with the path to cutjoin.sage on your computer
load "/home/tom/maths/free_sigma/cutjoin.sage"
///
}}}

{{{id=2|
L=[4,2]

for alpha in Partitions(sizePart(L)):
    print Smult(L,alpha), alpha
///
2 [6]
1 [5, 1]
2 [4, 2]
2 [4, 1, 1]
1 [3, 3]
2 [3, 2, 1]
1 [3, 1, 1, 1]
1 [2, 2, 2]
2 [2, 2, 1, 1]
1 [2, 1, 1, 1, 1]
0 [1, 1, 1, 1, 1, 1]
}}}