Does Python need to indicate encoding at the beginning of a file?

Question

Python

Please tell me how to format the file.
Some sources indicate that you need to write at the beginning:

# coding : utf-8
# PEP-8

On the github, someone writes only this:
# -*- coding: utf-8 -*-
And Google, for example, does not indicate either one or the other, and leaves only information about the license at the beginning of the file:

# Copyright (C) 2018 Google Inc.
# Licensed under http://www.apache.org/licenses/LICENSE-2.0 <see LICENSE file>

Answer 1

https://www.python.org/dev/peps/pep-0263/#examples
Worth mentioning if using weird IDEs/editors or python2 that can mess with utf-8

Answer 2

If you want a different input / output from en_GB (for example, ru_RU), specify
# -*- coding: utf-8 -*-