Function read_line 

pub fn read_line(
    reader: &mut Reader<'_>,
    start: &BytesStart<'_>,
    is_start: bool,
) -> Result<Line, Error>

Parses a CT_LineProperties-typed element (<a:ln>, or the same type under a different name, e.g. PresentationML’s table cell borders <a:lnL>/<a:lnR>/<a:lnT>/<a:lnB> — see crate::write_line_named for the writer-side symmetric case), from a reader positioned right at its own Start/Empty event — unlike read_fill/read_color, which scan forward looking for a bare choice, the caller here has already matched the element by name (its own name isn’t fixed, unlike <a:solidFill>/<a:srgbClr>) and hands over its start/is_start directly, the same contract read_shape_properties’s own internal <a:xfrm>/<a:ln> handling uses.