Extra tick not showing in the Altair bar chart

So I started with Altair, so far very intuitive, but I can't make an extra tick position to show, no matter what I do. My code looks like this:

alt.Chart(df3).mark_bar(opacity=0.8).encode(
    x=alt.X('sname'
            , sort='-y'
            , axis=alt.Axis(title="",labelFontSize=16)),
    y=alt.Y('W10',axis=alt.Axis(title="",titleFont=font
                                ,labelFontSize=16,  titleFontSize=30
                               ,values=list(range(12)) 
                                ,tickExtra=True
                               )),
      
    color=alt.condition(
        alt.datum.form=='Cold',  # If the rating is 80 it returns True,
        alt.value('#ff6666'),      # and the matching bars are set as green.
        # and if it does not satisfy the condition 
        # the color is set to steelblue.
        alt.value('#003366')
    )
).properties(width=700 #, height=700
            ).configure(
)

And I get something like this:

Column "W10" has the highest value of 9 in my dataset. But the max possible value is 10, and I would like to have that offset, that extra tick. But not matter what I do, it is not showing. I tried playing with various tick parameters, but no luck. Like now, I defined a range of 12, and I set "tickExtra=True" but not working.

Am I doing something wrong here, or it is kind of a bug?

Thanks!

To specify exact axis limits, you can use the domain property of the scale.

alt.Chart(cars).mark_point().encode(
    alt.X('Acceleration:Q',
        scale=alt.Scale(domain=(5, 20))
    ),
    y='Horsepower:Q'
)

See: https://altair-viz.github.io/user_guide/customization.html#adjusting-axis-limits