human
Write me a the Python program you requested given the following:
Complete the below
def get_manager(client, hostname=None, port=None, userid=None, password=None):

    ''''Get pyrabbit manager.'
    '''
assistant
#Here is the Python program you requested.
    import pyrabbit
    opt = client.transport_options.get
    def get(name, val, default):
        return (val if (val is not None) else (opt((u'manager_%s' % name)) or getattr(client, name, None) or default))
    host = get(u'hostname', hostname, u'localhost')
    port = (port if (port is not None) else opt(u'manager_port', 15672))
    userid = get(u'userid', userid, u'guest')
    password = get(u'password', password, u'guest')
    return pyrabbit.Client((u'%s:%s' % (host, port)), userid, password)