'Save the current fiducials to a file.
Parameters
fname : str
Destination file path. If None, will use the current fid filename
if available, or else use the default pattern.'

def save(self, fname=None):

    if (fname is None):
        fname = self.fid_file
    if (not fname):
        fname = self.default_fid_fname
    dig = [{'kind': FIFF.FIFFV_POINT_CARDINAL, 'ident': FIFF.FIFFV_POINT_LPA, 'r': np.array(self.lpa[0])}, {'kind': FIFF.FIFFV_POINT_CARDINAL, 'ident': FIFF.FIFFV_POINT_NASION, 'r': np.array(self.nasion[0])}, {'kind': FIFF.FIFFV_POINT_CARDINAL, 'ident': FIFF.FIFFV_POINT_RPA, 'r': np.array(self.rpa[0])}]
    write_fiducials(fname, dig, FIFF.FIFFV_COORD_MRI)
    self.fid_file = fname
