_pickle.UnpicklingError: invalid load key, '\xef'. | error python

I am using discord.py. On my on_ready() function I want to open the open, read, and write on the pkl file. but it keeps giving this error:

data = pickle.load(file)
_pickle.UnpicklingError: invalid load key, '\xef'.

This is the code I was using:

@bot.event
async def on_ready():
try:
    with open("test.pkl", "rb") as file:
        data = pickle.load(file)
        print(data)

    with open("test.pkl", 'wb') as file:
        file.close()

    with open("test.pkl", 'wb') as file:
        pickle.dump({}, file)
except:
    raise