<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def cardinality(gym_space):
 """Number of elements that can be represented by the space. Makes the most sense for Discrete or Box type with integral dtype, ex: number of actions in an action space. Args: gym_space: The gym space. Returns: np.int64 number of observations that can be represented by this space, or returns None when this doesn't make sense, i.e. float boxes etc. Raises: NotImplementedError when a space's cardinality makes sense but we haven't implemented it. """


  if (gym_space.dtype == np.float32) or (gym_space.dtype == np.float64):
    tf.logging.error("Returning None for a float gym space's cardinality: ",
                     gym_space)
    return None

  if isinstance(gym_space, Discrete):
    return gym_space.n

  if isinstance(gym_space, Box):
    # Construct a box with all possible values in this box and take a product.
    return np.prod(gym_space.high - gym_space.low + 1)

  raise NotImplementedError