**TypeError: _update_params_on_kvstore() takes exactly 4 arguments (3 given)**

[xuwentang]

Traceback (most recent call last):
File "experiments/rfcn/rfcn_end2end_train_test.py", line 19, in
train_end2end.main()
File "experiments/rfcn/../../rfcn/train_end2end.py", line 164, in main
config.TRAIN.begin_epoch, config.TRAIN.end_epoch, config.TRAIN.lr, config.TRAIN.lr_step)
File "experiments/rfcn/../../rfcn/train_end2end.py", line 157, in train_net
arg_params=arg_params, aux_params=aux_params, begin_epoch=begin_epoch, num_epoch=end_epoch)
File "experiments/rfcn/../../rfcn/core/module.py", line 969, in fit
self.update()
File "experiments/rfcn/../../rfcn/core/module.py", line 1051, in update
self._curr_module.update()
File "experiments/rfcn/../../rfcn/core/module.py", line 572, in update
self._kvstore)
TypeError: _update_params_on_kvstore() takes exactly 4 arguments (3 given)

[xuwentang]

msracver/Deformable-ConvNets#62

[Horacehxw]

I tried this based on new mxnet documentation and it works fine so far.

def update(self):
       """Update parameters according to the installed optimizer and the gradients computed
       in the previous forward-backward batch.
       """
       assert self.binded and self.params_initialized and self.optimizer_initialized

       self._params_dirty = True
       # FIXME: need 4 arguments here.
       if self._update_on_kvstore:
           _update_params_on_kvstore(self._exec_group.param_arrays,
                                     self._exec_group.grad_arrays,
                                     self._kvstore,
                                     self._exec_group.param_names)
       else:
           _update_params(self._exec_group.param_arrays,
                          self._exec_group.grad_arrays,
                          updater=self._updater,
                          num_device=len(self._context),
                          kvstore=self._kvstore)