human
Complete the below
def by_content_type():

    '''':return:
    A key function that returns a 2-tuple (content_type, (msg[content_type],)).
    In plain English, it returns the message\'s *content type* as the key,
    and the corresponding content as a positional argument to the handler
    function.'
    '''
assistant
#Here is the Python code you requested.
    def f(msg):
        content_type = glance(msg, flavor='chat')[0]
        return (content_type, (msg[content_type],))
    return f