def serialize_value(value):
    if not value:
        return None
    return value.isoformat()
Returns the color in the line, if any hsl is found.
dataset/ETHPy150Open STIXProject/python-stix/stix/utils/dates.py/serialize_value--crossover with--dataset/ETHPy150Open ggordan/GutterColor/line.py/Line.hsl_color