def crawl(name, mapping):
    try:
        result = _crawl(name, mapping)
        # Handle default tasks
        if isinstance(result, _Dict):
            if getattr(result, 'default', False):
                result = result.default
            # Ensure task modules w/ no default are treated as bad targets
            else:
                result = None
        return result
    except (KeyError, __HOLE__):
        return None
dataset/ETHPy150Open fabric/fabric/fabric/task_utils.py/crawl