JupyterDash unable to access callback-modified objects in next cell

Dash Python
1

Let’s suppose that I want to make a Dash app call from a python class, within a jupyter notebook/lab (hence using jupyter_dash), do some stuffs and finally access to the modified object.
I am currently falling short on this last task and couldn’t make it work in any way. Here a minimal working example:

import pandas as pd
import numpy as np

from flask import Flask

import dash_bootstrap_components as dbc
from dash.dependencies import Input, Output, State
from dash import html, dcc

from jupyter_dash import JupyterDash

# Initialize flask server and dash app
server = Flask(__name__)

app = JupyterDash(
    __name__,
    server=server,
    external_stylesheets=[
        dbc.themes.BOOTSTRAP,
    ],
)


class DropCol:
  
    def __init__(self, server, app, mode="inline", debug=True):
        self.mode = mode
        self.debug = debug
        self.app = app
        self.server = server
        self.callbacks(self.app)
    

    def __call__(self, df: pd.DataFrame):
        
       # Create layout based on dataframe
        col_options = [{"label": c, "value": c} for c in df.columns]
        data_store = dcc.Store(id="data-store", data=df.to_json(date_format="iso", orient="split"))
        dropdown = dcc.Dropdown(id="cols", options=col_options)
        
        self.app.layout = html.Div(
            id="layout",
            children=[
                data_store,
                dropdown
            ],
        )
        
        # run the app
        self.app.run_server(mode=self.mode, debug=self.debug, port="8000")
    
    def callbacks(self, app):
        """Initialize app callbacks"""

        @app.callback(
            Output("data-store", "data"),
            Input("cols", "value"),
            State("data-store", "data"),
            prevent_initial_call=True,
        )
        def on_col_selection(col_name, df_jsonified):
            
            df = (pd.read_json(df_jsonified, orient="split")
                  .drop(col_name, axis=1)
                )
            return df.to_json(date_format="iso", orient="split")
    
    @property    
    def get_data_frame(self):
        """property to retrieve dataframe from data-store"""
        df_json = self.app.layout['data-store'].data
        return pd.read_json(df_json, orient="split")


# Sample dataframe
df = pd.DataFrame({
    "a": np.arange(10),
    "b": np.random.randn(10)
})

col_dropper = DropCol(server, app, mode="inline")
col_dropper(df)
"""
Here I select one of the column from the dropdown, hence I expect that the json `data-store` has  one column remaining.
However this is not the case when I access the data in the following cell
"""

col_dropper.get_data_frame.head(3)
|    |   a |         b |
|---:|----:|----------:|
|  0 |   0 |  1.0964   |
|  1 |   1 | -0.30562  |
|  2 |   2 |  1.34761  |

As you can see, the stored dataframe I am able to access has all the columns, even after I select one in the above call.

Suppose that I select column b, then the expected output is:

col_dropper.get_data_frame.head(3)
|    |   a |
|---:|----:|
|  0 |   0 |
|  1 |   1 |
|  2 |   2 |

Packages versions I am using are: dash==2.0.0, dash_bootstrap_components==1.0.1, flask==2.0.1, jupyter_dash==0.4.0

Is there any way to accomplish such task?