oonidata sync generated None in the filename

[Arturo Filastò]

From slack:

I have some additional question. I am seeing in some of the dates there are two different file:
2020010400_None_webconnectivity.jsonl.gz
2020010400_PK_webconnectivity.jsonl.gz
Although I am specifying the Country Code I am seeing two different. What is the reason behind that?

So, using the following command:

poetry run python3.9 oonidata/main.py sync --start-day 2019-01-01 --end-day 2019-12-31 --probe-cc CN --test-name web_connectivity --output-dir /media/dheeman/ooni_data_dump/China/2019

Is generating a lot of jsonl.gz files with None instead of the Country Code CN