<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def url_join(base, *args):
 """ Helper function to join an arbitrary number of url segments together. """

    scheme, netloc, path, query, fragment = urlsplit(base)
    path = path if len(path) else "/"
    path = posixpath.join(path, *[('%s' % x) for x in args])
    return urlunsplit([scheme, netloc, path, query, fragment])