saving as an svg is not straightforward for each engine

[chanana]

for engine in ["plotly", "matplotlib", "bokeh"]:
    print(engine)
    p = Plotter(engine)
    fig = p.make_mirror_plot(
        mz1, int1, mz2, int2, label_top="top", label_bottom="bottom", title="mirror plot"
    )
    hv.save(fig, f"../example_data/figs/mirror_plot_{engine}.svg", fmt="svg")

gives

---------------------------------------------------------------------------
Exception                                 Traceback (most recent call last)
Cell In[6], line 7
      3 p = Plotter(engine)
      4 fig = p.make_mirror_plot(
      5     mz1, int1, mz2, int2, label_top="top", label_bottom="bottom", title="mirror plot"
      6 )
----> 7 hv.save(fig, f".[./example_data/figs/mirror_plot_](https://file+.vscode-resource.vscode-cdn.net/Users/shaurya/code/mspaint/notebooks/example_data/figs/mirror_plot_){engine}.svg", fmt="svg")

File [~/code/mspaint/.venv/lib/python3.9/site-packages/holoviews/util/__init__.py:801](https://file+.vscode-resource.vscode-cdn.net/Users/shaurya/code/mspaint/notebooks/~/code/mspaint/.venv/lib/python3.9/site-packages/holoviews/util/__init__.py:801), in save(obj, filename, fmt, backend, resources, toolbar, title, **kwargs)
    799     if formats[-1] in supported:
    800         filename = '.'.join(formats[:-1])
--> 801 return renderer_obj.save(obj, filename, fmt=fmt, resources=resources,
    802                          title=title)

File [~/code/mspaint/.venv/lib/python3.9/site-packages/holoviews/plotting/renderer.py:579](https://file+.vscode-resource.vscode-cdn.net/Users/shaurya/code/mspaint/notebooks/~/code/mspaint/.venv/lib/python3.9/site-packages/holoviews/plotting/renderer.py:579), in Renderer.save(self_or_cls, obj, basename, fmt, key, info, options, resources, title, **kwargs)
    573     param.main.param.warning("Supplying plot, style or norm options "
    574                        "as keyword arguments to the Renderer.save "
    575                        "method is deprecated and will error in "
    576                        "the next minor release.")
    578 with StoreOptions.options(obj, options, **kwargs):
--> 579     plot, fmt = self_or_cls._validate(obj, fmt)
    581 if isinstance(plot, Viewable):
    582     from bokeh.resources import CDN, INLINE, Resources

File [~/code/mspaint/.venv/lib/python3.9/site-packages/holoviews/plotting/renderer.py:314](https://file+.vscode-resource.vscode-cdn.net/Users/shaurya/code/mspaint/notebooks/~/code/mspaint/.venv/lib/python3.9/site-packages/holoviews/plotting/renderer.py:314), in Renderer._validate(self, obj, fmt, **kwargs)
    312 all_formats = set(fig_formats + holomap_formats)
    313 if fmt not in all_formats:
--> 314     raise Exception("Format %r not supported by mode %r. Allowed formats: %r"
    315                     % (fmt, self.mode, fig_formats + holomap_formats))
    316 self.last_plot = plot
    317 return plot, fmt

Exception: Format 'svg' not supported by mode 'default'. Allowed formats: ['html', 'auto', 'png', 'widgets', 'scrubber', 'gif', 'auto', None]

stackOverflow says: https://stackoverflow.com/a/65267737