unique.py

def unique(items):
    """
    Take a list or tuple. Return the same type containing only unique items.

    >>> unique([1, 2, 2, 3])
    [1, 2, 3]
    >>> unique((1, 2, 2, 3))
    (1, 2, 3)
    """
    i = set(items)
    return type(items)(i)