code: def get_last_traded_dt(self, asset, dt):
          
          country_code = self._country_code_for_assets([asset.sid])
          return self._readers[country_code].get_last_traded_dt(asset, dt)
docs: Get the latest day on or before ``dt`` in which ``asset`` traded.
  
          If there are no trades on or before ``dt``, returns ``pd.NaT``.
  
          Parameters
          ----------
          asset : zipline.asset.Asset
              The asset for which to get the last traded day.
          dt : pd.Timestamp
              The dt at which to start searching for the last traded day.
  
          Returns
          -------
          last_traded : pd.Timestamp
              The day of the last trade for the given asset, using the
              input dt as a vantage point.