def target_urls(self, year=None):
        return [item['raw_url'] for item in self.mappings(year)]
An iterator of all legal window lengths on a buffer of a given length.
dataset/ETHPy150Open openelections/openelections-core/openelex/us/id/datasource.py/Datasource.target_urls--crossover with--dataset/ETHPy150Open quantopian/zipline/tests/pipeline/test_adjusted_array.py/valid_window_lengths