code: def defvalkey(js, key, default=None, take_none=True):
      
      if js is None:
          return default
      if key not in js:
          return default
      if js[key] is None and not take_none:
          return default
      return js[key]
docs: Returns js[key] if set, otherwise default. Note js[key] can be None.
      :param js:
      :param key:
      :param default:
      :param take_none:
      :return: