'Run the nth empty ingest.
Returns
wrote_to : str
The timestr of the bundle written.'

def _empty_ingest(self, _wrote_to=[]):

    if (not self.bundles):
        @self.register('bundle', calendar_name='NYSE', start_session=pd.Timestamp('2014', tz='UTC'), end_session=pd.Timestamp('2014', tz='UTC'))
        def _(environ, asset_db_writer, minute_bar_writer, daily_bar_writer, adjustment_writer, calendar, start_session, end_session, cache, show_progress, output_dir):
            _wrote_to.append(output_dir)
    _wrote_to[:] = []
    self.ingest('bundle', environ=self.environ)
    assert_equal(len(_wrote_to), 1, msg='ingest    was    called    more    than    once')
    ingestions = self._list_bundle()
    assert_in(_wrote_to[0], ingestions, msg='output_dir    was    not    in    the    bundle    directory')
    return _wrote_to[0]
