Given an Interval or IntervalIndex, return the corresponding interval with
    closed bounds.

def _get_interval_closed_bounds(interval):
    """
    Given an Interval or IntervalIndex, return the corresponding interval with
    closed bounds.
    """
    left, right = interval.left, interval.right
    if interval.open_left:
        left = _get_next_label(left)
    if interval.open_right:
        right = _get_prev_label(right)
    return left, right