the functional approach of ".".join

list_join.py

def list_join(sep, items):
    """ method wrapper for str.join alternative.
    >>> foo = ['foo', 'bar', 'baz']
    >>> sep = ","
    >>> sep.join(foo)
    'foo,bar,baz'
    >>> list_join(',', foo)
    'foo,bar,baz'
    """
    return reduce(lambda x, y: '%s%s%s' % (x, sep, y), items)