You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: fiff_write_dig_file.m
    path of file: ./repos/spm12/external/mne
    
    the code of the file until where you have to start completion: function fiff_write_dig_file(filename,lpa,nas,rpa,hpi,eeg,eegref,extra)
%
% function fiff_write_dig_file(filename,lpa,nas,rpa,hpi,eeg,eegref,extra)
%
% Create a fif file containing the Polhemus data
%
% filename      Output file name
%
% The following need to be specified in the Neuromag MEG
% coordinate system in meters
%
% lpa           Left auricular point
% nas           Nasion

    
function fiff_write_dig_file(filename,lpa,nas,rpa,hpi,eeg,eegref,extra)
%
% function fiff_write_dig_file(filename,lpa,nas,rpa,hpi,eeg,eegref,extra)
%
% Create a fif file containing the Polhemus data
%
% filename      Output file name
%
% The following need to be specified in the Neuromag MEG
% coordinate system in meters
%
% lpa           Left auricular point
% nas           Nasion
% rpa           Right auricular point
% hpi           HPI coil locations               (optional)
% eeg           EEG electrode locations          (optional)
% eegref        EEG reference electrode location (optional)
% extra         Additional head surface points   (optional)
%

%
%   Author : Matti Hamalainen, MGH Martinos Center
%   License : BSD 3-clause
%
%   Revision 1.1  2008/06/04 16:23:24  msh
%   Added fiff_write_dig_file.m
%
%


%
me   = 'MNE:mne_create_dig_file';
%
global FIFF;
if isempty(FIFF)
   FIFF = fiff_define_constants();
end