Subtract two lists of parameters

    :param param_list_left: list of numpy arrays
    :param param_list_right: list of numpy arrays
    :return: list of numpy arrays

def subtract_params(param_list_left, param_list_right):
    """Subtract two lists of parameters

    :param param_list_left: list of numpy arrays
    :param param_list_right: list of numpy arrays
    :return: list of numpy arrays
    """
    res = []
    for x, y in zip(param_list_left, param_list_right):
        res.append(x - y)
    return res