Prework

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Description

great_tables.loc.spanner_labels does not work for levels above the lowest level

Reproducible example

from great_tables import GT, exibble, loc, style
gt = (
    GT(exibble.loc[[0, 1], ["char", "fctr", "row"]])
    .tab_spanner("spanner1_level0", ["fctr"], level=0)
    .tab_spanner("spanner2_level0", ["char"], level=0)
    .tab_spanner("spanner_level1", ["char", "fctr"], level=1)
)
color1 = "#a6cee3"
color2 = "#b15928"
(
    gt.tab_style(style.fill(color1), loc.spanner_labels(ids=["spanner1_level0"]))
    .tab_style(style.fill(color2), loc.spanner_labels(ids=["spanner2_level0"]))
    .tab_style(style.fill(color2), loc.spanner_labels(ids=["spanner_level1"]))
)

• Post a minimal reproducible example (MRE) so the maintainer can troubleshoot the problems you identify. A reproducible example is:
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Expected result

spanner_level1 should be filled with same color as spanner2_level0, but is not filled at all.

Development environment

• Operating System: Linux
• great_tables Version: 0.17.0

Additional context