Use collections.abc instead of list

[leon1995]

Summary

It would be nice if instead of the types like list or dict Sequence and Mapping could be used from collections.abc module

What is the feature request for?

The core library

The Problem

because the type is a list, a user can manually add a instance of something to a message.

The Ideal Solution

Sequence and Mapping are immutable types

The Current Solution

No response