python dictionary flatten

gistfile1.py

def flatten(l):
    if isinstance(l, list):
        if not l:
            return []
        else:
            return flatten(l[0]) +  flatten(l[1:])
    return [l]


def dict_flatten(d):
    def dict_to_list(d):
        if not d:
            return []
        key_list = list(d)
        if not key_list:
            return []
        else:
            return key_list + [dict_flatten(d[k]) for k in key_list]
    return flatten(dict_to_list(d))