Note thatasyncsteem and asyncsteem3 are seperate code bases for seperate python versions. There are features in asyncsteem (for Python 2.x) that aren't (fully) ported to asyncsteem3 (Python 3.x). The code for t post was done with the Python2 version. I'm currently working on a new library, txjsonrpcqueue that is currently still in a state of flux but that aims to become a library that works on both Python2 and Python3, and on Python3 works with both Twisted and asyncio, until it is production ready, I keep main the Python2 codebase, and @scottyeager is the man to see about the Python 3 codebase.

If the Python2 code is running, there should be a log file where you can see what is going on.
If you have it running for more than an hour, and the stream of block is working OK, you should at least see lines something like this once an hour:

2019-05-06T04:00:11+0000 [asyncsteem#info] Blockchain time mark: '2019-05-06T04:00:00'

Are you seeing those?

The code of this post by the way is in the asyncsteem source tree under sample_code/flag-stream

Hope this helps