Helper function which returns an array
    with the Intervals' boundaries.

def _interval_to_bound_points(array):
    """
    Helper function which returns an array
    with the Intervals' boundaries.
    """

    array_boundaries = np.array([x.left for x in array])
    array_boundaries = np.concatenate(
        (array_boundaries, np.array([array[-1].right])))

    return array_boundaries