Python combinations of n elements

def combinations(lst,n):
    if n == 1: # every item is a combination
        return list(map(lambda x: [x], lst))
    elif len(lst) == n: # there is only one combination
        return [list(lst)]
    else:
        first = lst[0]
        rest = lst[1:]
        # similar to coin change, either include or not include the first item
        # if include the first item, add first to the combinations of the rest items that form n-1 combi
        return list(map(lambda x: [first] + x , combinations(rest, n-1))) + combinations(rest,n)