Handle empty request body in post method via 400 status code

I am trying to create an error handler in my Flask API such that when an empty body is sent in a post request, the response should generate a jsonified 400 error message and give the status code as 400 Bad Request on Postman. But currently I am getting 400 error message in the response body and 500 status code on Postman [1]: https://i.stack.imgur.com/DV1BX.png

import pyodbc
from pytz import timezone
from flask import Flask, jsonify, request, Response
from datetime import datetime, timedelta
from waitress import serve
from flask_api import status

app = Flask(__name__)

server = 'bla'
database = 'bla'
username = 'bla'
password = 'bla'
driver = '{ODBC Driver 18 for SQL Server}'

connection_string = 'DRIVER='+driver+';SERVER=tcp:'+server + \
    ';PORT=bla;DATABASE='+database+';UID='+username+';PWD=' + password


def hello(data):

    try:
        
        if data["url"] == "":
            return jsonify({"message": "Error Code : 404 - Not found"}), status.HTTP_404_NOT_FOUND
        
               
        Headers = {"Content-Type": "application/json",
                   "Authorization": "Bearer " + access_token}

        resp = requests.post(
            data["url"], json=bla, headers=Headers)

        if resp.status_code == 200:

            values = resp.json()["value"]

            {perform some operation here}
            
            return filtered_values, status.HTTP_200_OK

        else:
            return resp.json()["error"]["message"],resp.status_code
    except Exception as e:
        print("Error", e)
        raise
    

@app.route("/")
def status():
    return jsonify({"status": "OK"}), status.HTTP_200_OK




@app.errorhandler(404)
def not_found(e):
    return jsonify({"message": str(e)}), status.HTTP_404_NOT_FOUND




@app.route("/somepath", methods=["GET", "POST"])
def details():
    if request.method == "POST":
        try:

            operation_data = request.get_json()

            
            data, code = hello(operation_data )

            if code != 200:
                return jsonify({"message": str(data)}), code

            else:
                if len(data) != 0 and data is not None:

                    conn = pyodbc.connect(connection_string)
                    cursor = conn.cursor()
                    
                    for d in data:
                        
                        cursor.execute(some query)

                    conn.commit()
                    cursor.close()
                    conn.close()
                    new_resp = jsonify({"message": "successful"})
                    return new_resp, status.HTTP_200_OK

                else:
                    new_resp = jsonify({"message": "nothing to do"})
                    return new_resp, status.HTTP_200_OK

        except Exception as exception:
            print(exception)
            return jsonify(str(exception)), status.HTTP_500_INTERNAL_SERVER_ERROR

    else:
        return jsonify({"status": str(request.method) + " - Method not allowed"}),status.HTTP_405_METHOD_NOT_ALLOWED

   
if __name__ == "__main__":
    app.run(host='0.0.0.0', port=8000, debug=True)
    # serve(app, listen='*:8000')```