<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def find_furious_yaml(config_file=__file__):
 """ Traverse directory trees to find a furious.yaml file Begins with the location of this file then checks the working directory if not found Args: config_file: location of this file, override for testing Returns: the path of furious.yaml or None if not found """

    checked = set()
    result = _find_furious_yaml(os.path.dirname(config_file), checked)
    if not result:
        result = _find_furious_yaml(os.getcwd(), checked)
    return result