How to get Up/Down weight from Weights() class

[jusong21]

Describe what you want to do
A clear and concise description of what the goal is.

I made weight which is Weights class and save scale factors like below.

from coffea.analysis_tools import Weights
import numpy as np

weight = Weights(6, storeIndividual=True)

sfs = np.array([0.997, 1.01, 1, 1, 1, 0.997])
sfs_up = np.array([1, 1.32, 1.01, 1, 1, 1])
sfs_down = np.array([0.992, 0.699, 0.995, 0.999, 0.999, 0.992])

weight.add("test_SF", sfs, sfs_up, sfs_down)

In the weight, there are several more scale factors with different names.
I tried the below.

w = weight.partial_weight(include=["test_SF"])

When print w, it gives below which is the same to the nominal values.

array([0.997, 1.01 , 1.   , 1.   , 1.   , 0.997])

I want to get Up/Down values of "test_SF". How can I do that?
Currently, I'm using coffea==0.7.22, I can't use the recent one because of package version.

Explain what documentation is missing
If someone else has this same goal, what do you think could be added to https://coffeateam.github.io/coffea/ to help them complete the task on their own?