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The elements of this struct have two types:
- Borders (upper, lower, left, right, horizontal, vertical); the borders are the structs com.sun.star.table.BorderLine2 which "add" style elements for the struct com.sun.star.table.BorderLine.
- Booleans (IsLeftLineValid, IsRightLineValid, IsTopLineValid, etc.). In writing, defining them as True to modify the line correspondingly, and False to ignore; meaning it keeps its current value.