add get num invokers

def get_invokers():

    return operations.get_invokers()

@backoffice_routes.route("/resources/numInvokers", methods=["GET"])

@jwt_required()

def get_num_invokers():

    return operations.get_num_invokers()

@backoffice_routes.route("/providers", methods=["GET"])

def get_providers():

import requests

from ..config import Config

import os

import json

class Operations:

        except Exception as e:

            return "Error when retreiving invoker list: ", e

    def get_num_invokers(self):

        # get invoker and user collections

        mycol = self.db.get_col_by_name(self.db.invokers)

        user_col = self.db.get_col_by_name_register(self.db.user)

        try:

            invokers = mycol.find({}, {"_id": 0})

            users = user_col.find({}, {"_id": 0})

            json_invokers = []

            for invoker in invokers:

                # user = user_col.find({

                # "list_invokers": invoker["api_invoker_id"]

                # }, 

                # {"_id": 0})

                # invoker.update(user)

                for user in users:

                    if invoker["api_invoker_id"] in user["list_invokers"]:

                        invoker["username"]=user["username"]

                json_invokers.append(invoker)

            num_invokers = len(json_invokers)

            return jsonify(num_invokers), 200

        except Exception as e:

            return "Error when retreiving number of invokers: ", e

    def get_invoker_security_context(self, invoker_id):

        security_context_col = self.db.get_col_by_name(