tari

def nested_append(nlist, element, depth):
    """Appends element to nlist at depth levels in, where levels are delimited
       by sublists and begin at 1 for the list root.  Levels prior to depth
       will be created if they do not exist, and depths less than 1 are
       treated as if they were 1.

       Example:
       >>> a = []
       >>> nested_append(a, '1.0', 1)
       # a = ['1.0']
       >>> nested_append(a, '2.0', 2)
       # a = ['1.0', ['2.0']]
       >>> nested_append(a, ['3.0','3.1'], 2)
       # a = ['1.0', ['2.0', ['3.0', '3.1']]]
       >>> nested_append(a, '1.1', 1)
       # a = ['1.0', ['2.0', ['3.0', '3.1']], '1.1']

       Note that the second call for level 2 is equivalent to two calls to
       nested_append at level 3 with elements '3.0' and '3.1'.
    if depth <= 1:
        # Have hit the target level
        nlist.append(element)
    else:
        if not isinstance(nlist[-1], list):
            # Next level doesn't exist yet, so create it
            nlist.append([])
        nested_append(nlist[-1], element, depth - 1)