Initialize parameters in the KVStore.

        Parameters with incomplete initialization are ignored.

def _init_params(self):
        """Initialize parameters in the KVStore.

        Parameters with incomplete initialization are ignored.

        """
        assert self._kv_initialized, "Cannot initialize parameters in KVStore " \
                                     "when KVStore is not initialized."
        params_to_init = []
        if self._kvstore:
            for param in self._params_to_init:
                if param._deferred_init:
                    params_to_init.append(param)
                else:
                    param_arrays = param._check_and_get(param._data, list)
                    idx = self._param2idx[param.name]
                    self._kvstore.init(idx, param_arrays[0])
                    if param._stype == 'default':
                        self._kvstore.pull(idx, param_arrays, priority=-idx)

        self._params_to_init = params_to_init