def __init__(self, vertical: str, cont: str, end: str):
        """
        Tree Render Style.
        Args:
            vertical: Sign for vertical line.
            cont: Chars for a continued branch.
            end: Chars for the last branch.
        """
        super().__init__()
        self.vertical = vertical
        self.cont = cont
        self.end = end
        assert len(cont) == len(vertical) == len(end), (
            f"'{vertical}', '{cont}' and '{end}' need to have equal length"
        )

        Tree Render Style.
        Args:
            vertical: Sign for vertical line.
            cont: Chars for a continued branch.
            end: Chars for the last branch.
        
xarray/core/datatree_render.py