def _validate_importers(importers):
    # They could have no importers, that's chill
    if importers is None:
        return None

    def _to_importer(priority, func):
        assert isinstance(priority, int), priority
        assert callable(func), func
        return (priority, _importer_callback_wrapper(func))

    # Our code assumes tuple of tuples
    return tuple(_to_importer(priority, func) for priority, func in importers)
Find the position of a character to the left.
dataset/ETHPy150Open dahlia/libsass-python/sass.py/_validate_importers--crossover with--dataset/ETHPy150Open zoofIO/flexx/translate_to_legacy.py/Token.find_backward