Traverse directory trees to find a contour.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 contour.yaml or None if not found

def find_contour_yaml(config_file=__file__, names=None):
    """
    Traverse directory trees to find a contour.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 contour.yaml or None if not found
    """
    checked = set()
    contour_yaml = _find_countour_yaml(os.path.dirname(config_file), checked,
                                       names=names)

    if not contour_yaml:
        contour_yaml = _find_countour_yaml(os.getcwd(), checked, names=names)

    return contour_yaml