Sort all lists within a list

If you have a list of lists such as:

lst = [[8, 4], [10,2]]

How do you sort it such that the lst is:

lst = [[4, 8], [2,10]]

I have tried:

lst = [i.sort() for i in lst]

and:

lst = list(map(lambda x: x.sort(), lst))

but these just return a list with None.

Any help would be much appreciated!

>Solution :

i.sort() sorts the list in-place and returns None. Instead, you use sorted():

lst = [sorted(i) for i in lst]

Or a for loop:

for i in lst:
    i.sort()