Save dash component or plotly express graph as json

I am creating a dash application and plotting graphs using plotly express. I trying to save the dash components and graphs into a json file using to_plotly_json(). But for pie chart graph, getting an error as below:

Error-1 The first argument to the plotly.graph_objs.layout.Template
constructor must be a dict or
an instance of :class:`plotly.graph_objs.layout.Template`
Error-1 The first argument to the plotly.graph_objs.layout.Template
constructor must be a dict or

Below is MWE:

import json

import dash_bootstrap_components as dbc
from dash import dcc

import plotly.express as px

import pandas as pd


def generate_pie_charts(df, template) -> list[dict[str, Any]]:
    pie_charts = list()

    for field in df.columns.tolist():
        
        value_count_df = df[field].value_counts().reset_index()        

        cols = value_count_df.columns.tolist()

        name: str = cols[0]
        value: str = cols[1]

        try:
            figure = px.pie(
                data_frame=value_count_df,
                values=value,
                names=name,
                title=f"Pie chart of {field}",
                template=template,
            ).to_plotly_json()

            pie_chart = dcc.Graph(figure=figure).to_plotly_json()
            
            pie_charts.append(pie_chart)
        except Exception as e:
            print(f"Error-1 {e}")
    
    return pie_charts


def perform_exploratory_data_analysis():
    rows = list()

    template = "darkly"

    info = {
        "A": ["a", "a", "b", "b", "c", "a", "a", "b", "b", "c", "a", "a", "b", "b", "c"],
        "B": ["c", "c", "c", "c", "c", "a", "a", "b", "b", "c", "a", "a", "b", "b", "c"],
    }

    df = pd.DataFrame(info)

    try:
        row = dbc.Badge(
            "For Pie Charts", color="info", className="ms-1"
        ).to_plotly_json()

        rows.append(row)

        row = generate_pie_charts(df, template)  

        rows.append(row)

        data = {"contents": rows}

        status = False

        msg = "Error creating EDA graphs."

        file = "eda.json"

        with open(file, "w") as json_file:
            json.dump(data, json_file)
            msg = "EDA graphs created."
            status = True

    except Exception as e:
        print(f"Error-2 {e}")

    result = (status, msg)

    return result


perform_exploratory_data_analysis()

What I am missing?

You need to explicitly load the theme template you want to use :

from dash_bootstrap_templates import load_figure_template

# ... 

def perform_exploratory_data_analysis():
    rows = list()

    template = "darkly"
    load_figure_template(template)

    # ...