Unicodedecodeerror 'utf-8' codec can't decode byte 0xe2 in position 0 invalid continuation byte how to solve?

Question

Python

I tried to change the encoding through notepad, no change.

from flask import Flask

app = Flask(__name__)
@app.route('/')
def hello() -> str:
    return '1'

app.run()

Can he swear in Cyrillic on the way?