src/transformers/utils/logging.py/_get_default_logging_level
def _get_default_logging_level():
    """
    If TRANSFORMERS_VERBOSITY env var is set to one of the valid choices return that as the new default level. If it is
    not - fall back to `_default_log_level`
    """
    env_level_str = os.getenv("TRANSFORMERS_VERBOSITY", None)
    if env_level_str:
        if env_level_str in log_levels:
            return log_levels[env_level_str]
        else:
            logging.getLogger().warning(
                f"Unknown option TRANSFORMERS_VERBOSITY={env_level_str}, "
                f"has to be one of: { ', '.join(log_levels.keys()) }"
            )
    return _default_log_level