Initializes the parameters and auxiliary states. By default this function
        does nothing. Subclass should override this method if contains parameters.

        Parameters
        ----------
        initializer : Initializer
            Called to initialize parameters if needed.
        arg_params : dict
            If not ``None``, should be a dictionary of existing `arg_params`. Initialization
            will be copied from that.
        aux_params : dict
            If not ``None``, should be a dictionary of existing `aux_params`. Initialization
            will be copied from that.
        allow_missing : bool
            If ``True``, params could contain missing values, and the initializer will be
            called to fill those missing params.
        force_init : bool
            If ``True``, will force re-initialize even if already initialized.
        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 init_params(self, initializer=Uniform(0.01), arg_params=None, aux_params=None,
                    allow_missing=False, force_init=False, allow_extra=False):
        """Initializes the parameters and auxiliary states. By default this function
        does nothing. Subclass should override this method if contains parameters.

        Parameters
        ----------
        initializer : Initializer
            Called to initialize parameters if needed.
        arg_params : dict
            If not ``None``, should be a dictionary of existing `arg_params`. Initialization
            will be copied from that.
        aux_params : dict
            If not ``None``, should be a dictionary of existing `aux_params`. Initialization
            will be copied from that.
        allow_missing : bool
            If ``True``, params could contain missing values, and the initializer will be
            called to fill those missing params.
        force_init : bool
            If ``True``, will force re-initialize even if already initialized.
        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.
        """
        pass