Recursively merge or update dict-like objects

update.py

import collections

def update(d, other):
    """Recursively merge or update dict-like objects.
    >>> from pprint import pprint
    >>> pprint(update({'k1': {'k2': 2}}, {'k1': {'k2': {'k3': 3}}, 'k4': 4}))
    {'k1': {'k2': {'k3': 3}}, 'k4': 4}
    >>> pprint(update({'k1': {'k2': 2}}, {'k1': {'k3': 3}}))
    {'k1': {'k2': 2, 'k3': 3}}
    >>> pprint(update({'k1': {'k2': 2}}, dict()))
    {'k1': {'k2': 2}}
    """

    for k, v in other.items():
        if isinstance(d, collections.Mapping):
            if isinstance(v, collections.Mapping):
                r = update(d.get(k, {}), v)
                d[k] = r
            else:
                d[k] = other[k]
        else:
            d = {k: other[k]}
    return d