def getitems(dictionary, *keys):
    """
    Get existing items of a dict lazy

    >>> d = {"henk": 1, "klaas": 2, "hent": 7}
    >>> r = getitems(d, "klaas")
    >>> list(r)
    [2]
    >>> r = getitems(d, "henk", "hent")
    >>> list(r)
    [1, 7]
    >>> r = getitems(d, "henk", "kak")
    >>> list(r)
    [1, None]
    """
    for key in keys:
        yield dictionary.get(key)
