human
Solve the following python programming problem given the following code:
def test_send_message_to_cell_fanout_cast(self) : 
    msg_runner = fakes.get_message_runner ('api-cell') 
    cell_state = fakes.get_cell_state ('api-cell', 'child-cell2') 
    message = messaging._TargetedMessage (msg_runner, self.ctxt, 'fake', { 
        
}, 'down', cell_state, fanout = True) 
    expected_server_params = { 
        'hostname' : 'rpc_host2', 
        'password' : 'password2', 
        'port' : 3092, 
        'username' : 'username2', 
        'virtual_host' : 'rpc_vhost2', 
} 
    expected_url = ('rabbit://%(username)s:%(password)s@%(hostname)s:%(port)d/%(virtual_host)s' % expected_server_params) 
    def check_transport_url(cell_state) : 
        return (cell_state.db_info ['transport_url'] == expected_url) 
rpcapi = self.driver.intercell_rpcapi 
    rpcclient = self.mox.CreateMockAnything () 
    self.mox.StubOutWithMock (rpcapi, '_get_client') 
    rpcapi._get_client (mox.Func (check_transport_url), 'cells.intercell.targeted').AndReturn (rpcclient) 
    rpcclient.prepare (fanout = True).AndReturn (cell_state) 
    rpcclient.cast (mox.IgnoreArg (), 'process_message', message = message.to_json ()) 
    self.mox.ReplayAll () 
    self.driver.send_message_to_cell (cell_state, message) 

    
    

    Fix the buggy line: rpcclient.prepare (fanout = True).AndReturn (cell_state)
assistant
#Here is Python program to fix the buggy line: rpcclient.

rpcclient.prepare (fanout = True).AndReturn (rpcclient)