def pairwise(things):
    """
    Return a list of pairs of adjacent elements from things.

    The last element of this list is the pair (things[-1], None).

    >>> list(pairwise(['a', 'b', 'c']))
    [('a', 'b'), ('b', 'c'), ('c', None)]

    >>> list(pairwise([]))
    []
    """
    return zip(things, things[1:] + [None])