human
Complete the below
def IdentifiersConcat():

    ''''String concatenation aggregator for the identifiers map'
    '''
 Give me a the Python code you requested?
assistant
#Here is the Python code you requested.
    def step(ctxt, key, val):
        ctxt.append((u'%s:%s' % (key, val)))
    def finalize(ctxt):
        return u','.join(ctxt)
    return ([], step, finalize)