def last_modified_time(path):
    return pd.Timestamp(os.path.getmtime(path), unit='s', tz='UTC')
This should generate an expression that picks the lower value for comparison.
dataset/ETHPy150Open quantopian/zipline/zipline/data/loader.py/last_modified_time--crossover with--dataset/ETHPy150Open thedrow/django-natural-query/tests/unit/test_date_natural_query_descriptor.py/DateNaturalQueryDescriptorTestCase.test_concated_gt_and_gte_operator_generates_the_right_expression_for_the_greater_than_or_equal_month_lookup