Patch

patch.py

def merge_patch(target, patch):
    if isinstance(patch, dict):
        if not isinstance(target, dict):
            target = {}
        for name, value in patch.iteritems():
            if value is None:
                if name in target:
                    del target[name]
            else:
                target[name] = merge_patch(target[name], value)
        return target
    else:
        return patch