def separated(items, sep=',', last=None):
    items = iter(items)
    next = items.next()
    for i in items:
        yield next, sep
        next = i
    yield next, last
Yield `(item, sep)` tuples, one for each element in `items`.
dataset/ETHPy150Open edgewall/trac/trac/util/presentation.py/separated