Data universe available at the current time.
        Universe contains the data passed in when creating a Backtest.
        Use this data to determine strategy logic.

def universe(self):
        """
        Data universe available at the current time.
        Universe contains the data passed in when creating a Backtest.
        Use this data to determine strategy logic.
        """
        # avoid windowing every time
        # if calling and on same date return
        # cached value
        if self.now == self._last_chk:
            return self._funiverse
        else:
            self._last_chk = self.now
            self._funiverse = self._universe.loc[:self.now]
            return self._funiverse