'Get the latest minute 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 minute.
dt : pd.Timestamp
The minute at which to start searching for the last traded minute.
Returns
last_traded : pd.Timestamp
The dt of the last trade for the given asset, using the input
dt as a vantage point.'

@abstractmethod
def get_last_traded_dt(self, asset, dt):

    pass
