docs: Error executing `realtime.md`'s code during building of local documentation

[Sagar Mishra]

Describe the bug
When I'm trying to build documentation, I'm met with a CellExecutionError:

Notebook error:
CellExecutionError in user_guide/plugins/realtime.md:
------------------
from folium import JsCode
m = folium.Map(location=[40.73, -73.94], zoom_start=12)
rt = folium.plugins.Realtime(
    "https://raw.githubusercontent.com/python-visualization/folium-example-data/main/subway_stations.geojson",
    get_feature_id=JsCode("(f) => { return f.properties.objectid; }"),
    interval=10000,
)
rt.add_to(m)
m
------------------


---------------------------------------------------------------------------
ImportError                               Traceback (most recent call last)
Cell In[2], line 1
----> 1 from folium import JsCode
      2 m = folium.Map(location=[40.73, -73.94], zoom_start=12)
      3 rt = folium.plugins.Realtime(
      4     "https://raw.githubusercontent.com/python-visualization/folium-example-data/main/subway_stations.geojson",
      5     get_feature_id=JsCode("(f) => { return f.properties.objectid; }"),
      6     interval=10000,
      7 )

ImportError: cannot import name 'JsCode' from 'folium' (C:\Users\sagar\miniconda3\envs\folium-dev\Lib\site-packages\folium\__init__.py)

You can ignore this error by setting the following in conf.py:

    nbsphinx_allow_errors = True

make: *** [Makefile:45: html] Error 2

To Reproduce

Run make html on the current head inside the /docs directory.

Expected behavior
Documentation build should be successful.

Environment (please complete the following information):

• Browser - irrelevant
• Jupyter Notebook or html files - realtime.md file which contains ipython code to create an HTML file.
• Python version - 3.12.2
• folium version - 0.15.1
• branca version - 0.7.1

Additional context
The code works. I'm not sure what context is missing for this failure.

Possible solutions
Since a user can run the failing code, we could ignore the errors by including the nbsphinx_allow_errors=True flag. Perhaps an easier win but doesn't address the problem.

folium is maintained by volunteers. Can you help making a fix for this issue?
I wasn't able to figure out the source of error during my initial inspection (I could be missing something very obvious), will take a look at it again if there's interest.

[Hans Then]

I was unable to reproduce this locally. Could it be a conflict between the version from the repository and the version of your pip installed folium? What is the output of python -c "from folium import JsCode"?

[Frank Anema]

That seems right @hansthen . JsCode was added in v0.16.0, so since you are on v0.15.1 you cannot import it. Can you try upgrading your version of Folium?