def send_marker(filename):
    if not os.path.exists('markers'):
        os.makedirs('markers')
    requested_filename = 'markers/{}'.format(filename)
    if os.path.isfile(requested_filename):
        return send_file(requested_filename, mimetype='image/png')
    else:
        result = re_pattern_marker.match(filename)
        if result is not None:
            cn = result.group(1)
            style = result.group(3)
            marker_filename = create_marker(cn, style)
            return send_file(marker_filename, mimetype='image/png')
        else:
            return("File {} neither found nor created".format(filename))
 def test_markers(self):
     self.assertEqual(create_marker('MY', 'g'), 'markers/MY_g.png')