add_vline fails in batch mode

I am using plotly 5.24.0 with python 3.10.12 in a vs-code interactive window.

The following example raises TypeError: unsupported operand type(s) for +=: 'NoneType' and 'str' in [...]/site-packages/plotly/basedatatypes.py:3995

import plotly.graph_objects as go

fig = go.Figure()

with fig.batch_update():
    fig.add_vline(1)

The same example without batch mode works fine:

import plotly.graph_objects as go

fig = go.Figure()

fig.add_vline(1)

Start with the batch_update context and add_vline example, then inspect plotly/basedatatypes.py around line 3995. Compare the failing batch-mode path with the working direct call and reproduce the TypeError using the versions in the report. Done means add_vline works inside fig.batch_update() without raising while preserving the existing direct-call behavior.