def _median(sorted_list):
    """Returns median value for specified sorted list.

    Parameters
    ----------
    arr: List[float]

    Returns
    -------
    float
    """
    assert sorted_list, "List is empty"

    n_items = len(sorted_list)
    return 0.5 * (sorted_list[(n_items - 1) // 2] + sorted_list[n_items // 2])