(first, second), iterable = spy('abcdefg', 2)
        >>> first
        'a'
        >>> second
        'b'

    The number of items requested can be larger than the number of items in
    the iterable:

        >>> iterable = [1, 2, 3, 4, 5]
        >>> head, iterable = spy(iterable, 10)
        >>> head
        [1, 2, 3, 4, 5]
        >>> list(iterable)
        [1, 2, 3, 4, 5]

    )