How to get all data from http/1.1 with transfer-encoding: chunked?

Question

Python

There is a code example https://pastebin.com/0gvM7Zj5
but in this example the received block already has the beginning of the next one, according to https://ru.wikipedia.org/wiki/Chunked_transfer_encoding everything should be correct.

example and the problem itself
6e42 this is already the next chunk, this is within 0x5392