Python solution to problem: "A person can walk/hop 1, 2 or 3 steps at a time, find all the possible ways to walk/hop down n steps"

gistfile1.txt

def append_return(n,L): 
    M=L[:]
    M.append(n)
    return M

def steps(n, L=[]):
    if n == 0:
        print L
    if n >= 1:
        steps(n-1, append_return(1,L))
    if n >= 2:
        steps(n-2, append_return(2,L))
    if n >= 3:
        steps(n-3, append_return(3,L))

since in python .apend does not return the mutated list, I wrote a helper function