def _require_dataset(self, symbol, year):
        key = self._key(symbol, year)
        return self.handle.require_dataset(key,
                                           (self.WORKING_DAYS_OF_YEAR, ),
                                           dtype=self.DTYPE)
Returns a query over all instances of this model from the datastore.
dataset/ETHPy150Open yinhm/datafeed/datafeed/datastore.py/Day._require_dataset--crossover with--dataset/ETHPy150Open AppScale/appscale/AppServer/google/appengine/ext/db/__init__.py/Model.all