cv2.Error: OpenCV (4.5.2) .Error: (-215: l'affirmation a échoué)! _RC.empty () en fonction 'CV :: CVTColor'

import cv2 #for image processing
import easygui #to open the filebox
import numpy as np #to store image
import imageio #to read image stored at particular path

import sys
import matplotlib.pyplot as plt
import os
import tkinter as tk
from tkinter import filedialog
from tkinter import *
from PIL import ImageTk, Image



top=tk.Tk()
top.geometry('400x400')
top.title('Cartoonify Your Image !')
top.configure(background='white')
label=Label(top,background='#CDCDCD', font=('calibri',20,'bold'))

def upload():
    ImagePath=easygui.fileopenbox()
    cartoonify(ImagePath)


def cartoonify(ImagePath):
    
    # read the image
    originalmage = cv2.imread(ImagePath)
    
    originalmage = cv2.cvtColor(originalmage, cv2.COLOR_BGR2RGB)
    #print(image)  # image is stored in form of numbers

cv2.error: OpenCV(4.5.2) C:\Users\runneradmin\AppData\Local\Temp\pip-req-build-vi271kac\opencv\modules\imgproc\src\color.cpp:182: error: (-215:Assertion failed) !_src.empty() in function 'cv::cvtColor'