Assign, i.e. copy parameters to all the executors.

        Parameters
        ----------
        arg_params : dict
            A dictionary of name to `NDArray` parameter mapping.
        aux_params : dict
            A dictionary of name to `NDArray` auxiliary variable mapping.
        allow_extra : boolean, optional
            Whether allow extra parameters that are not needed by symbol.
            If this is True, no error will be thrown when arg_params or aux_params
            contain extra parameters that is not needed by the executor.

def set_params(self, arg_params, aux_params, allow_extra=False):
        """Assign, i.e. copy parameters to all the executors.

        Parameters
        ----------
        arg_params : dict
            A dictionary of name to `NDArray` parameter mapping.
        aux_params : dict
            A dictionary of name to `NDArray` auxiliary variable mapping.
        allow_extra : boolean, optional
            Whether allow extra parameters that are not needed by symbol.
            If this is True, no error will be thrown when arg_params or aux_params
            contain extra parameters that is not needed by the executor.
        """
        for exec_ in self.execs:
            exec_.copy_params_from(arg_params, aux_params, allow_extra_params=allow_extra)