change context manager for temporary auto-reverted `figure.layout`

Instead of

fig.layout.showlegend = False
fig.write_image('plot.pdf')
fig.layout.showlegend = True

it would be nice to write

from plotly.express import plotly_patch  # or similar

with plotly_patch(fig.layout, showlegend=False):
    fig.write_image('plot.pdf')

I tried

from unittest.mock import patch

with patch.dict(fig.layout, showlegend=False):
    fig.write_image('plot.pdf')

which unfortunately doesn't correctly restore the previous value but tries to delete the patched keys which is undesired behavior and raises AttributeError to boot:

   1906 """Unpatch the dict."""
   1907 if self._original is not None:
-> 1908     self._unpatch_dict()
...
   1934 keys = list(in_dict)
   1935 for key in keys:
-> 1936     del in_dict[key]

AttributeError: __delitem__

Related

Found this forum post where such a context manager was welcomed.

issue ではソースファイルもテストも指定されていません。まず figure layout の変更と復元の動作を見つけ、次に context manager が既存の値を保持し、fig.write_image('plot.pdf'); の後に復元する方法を調べてください。done には、layout のキーを削除せずに一時的な showlegend の変更を対象とするカバレッジを含める必要があります。