human
I wrote the below code

    def step(ctxt, ndx, author, sort, link):
        if (author is not None):
            ctxt[ndx] = u':::'.join((author, sort, link))
    def finalize(ctxt):
        keys = list(ctxt.iterkeys())
        l = len(keys)
        if (l == 0):
            return None
        if (l == 1):
            return ctxt[keys[0]]
        return u':#:'.join([ctxt[v] for v in sorted(keys)])
    return ({}, step, finalize)

What's a good function header?
 Here's a good function header?
assistant
#Here's a good function header.

def AumSortedConcatenate():