def mask_pandas_args(self, kwargs):
        pandas_kwargs = {key: val for (key, val) in iteritems(kwargs)
                         if key in ALLOWED_READ_CSV_KWARGS}
        if 'usecols' in pandas_kwargs:
            usecols = pandas_kwargs['usecols']
            if usecols and self.date_column not in usecols:
                # make a new list so we don't modify user's,
                # and to ensure it is mutable
                with_date = list(usecols)
                with_date.append(self.date_column)
                pandas_kwargs['usecols'] = with_date

        # No strings in the 'symbol' column should be interpreted as NaNs
        pandas_kwargs.setdefault('keep_default_na', False)
        pandas_kwargs.setdefault('na_values', {'symbol': []})

        return pandas_kwargs
dataset/ETHPy150Open quantopian/zipline/zipline/sources/requests_csv.py/PandasCSV.mask_pandas_args/original