<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def check_type_of_param_list_elements(param_list):
 """ Ensures that all elements of param_list are ndarrays or None. Raises a helpful ValueError if otherwise. """

    try:
        assert isinstance(param_list[0], np.ndarray)
        assert all([(x is None or isinstance(x, np.ndarray))
                    for x in param_list])
    except AssertionError:
        msg = "param_list[0] must be a numpy array."
        msg_2 = "All other elements must be numpy arrays or None."
        total_msg = msg + "\n" + msg_2
        raise TypeError(total_msg)

    return None