Python UnpicklingError: invalid load key, '\xef' [closed]

I am new to python and came across a object deserialisation issue (unpickling) while testing a program on jupyter lab.

I am trying to serialize and deserialize object of Employee class as below.

- Definition of Employee class:

class Employee:
    def __init__(self, id, name, salary):
        self.id = id
        self.name = name
        self.salary = salary


    def display(self):
        print('{:5d} -- {:20s} -- {:10.2f}'.format(self.id, self.name, self.salary))

- Code to pickle Employee Object:

import pickle

file = open('employee-data.csv', 'wb')

n = int(input('How many employees ?'))

for i in range(n):
    id = int(input('Enter the Employee id:'))
    name = input('Enter the Employee name:')
    salary = float(input('Enter the Employee salary:'))

    ob = Employee(id, name, salary)

    pickle.dump(ob,file)

file.close()

- Code to unpickle Employee Object:

import pickle

file2 = open('employee-data.csv', 'rb')

print('Employee Details ....')

while True:
    try:
        obj = pickle.load(file2)
        obj.display()
    except EOFError:
        print('End of File Reached ...')
        break

file2.close()

Error:

> ---------
UnpicklingError   Traceback (most recent call
> last) Cell In[5], line 9
>       7 while True:
>       8     try:
> ----> 9         obj = pickle.load(file2)
>      10         obj.display()
>      11     except EOFError:
> 
> UnpicklingError: invalid load key, '\xef'.

Following snapshot shows that the code to serialize the object has run successfully. And the file was created.

What can be the problem here ? Any suggestions/feedbacks appreciated.