def return_hdr(self):
        """Return the header for further use.

        Returns
        -------
        subj_id : str
            subject identification code
        start_time : datetime
            start time of the dataset
        s_freq : float
            sampling frequency
        chan_name : list of str
            list of all the channels
        n_samples : int
            number of samples in the dataset
        orig : dict
            additional information taken directly from the header
        """

        subj_id = self._header['name'] + ' ' + self._header['surname']
        chan_name = [ch['chan_name'] for ch in self._header['chans']]

        return subj_id, self._header['start_time'], self._header['s_freq'], chan_name, self._n_smp, self._header