I use pytest --slack_hook=https://hooks.slack.com/services/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 --slack_username=IGNORED --slack_channel='Dave Far'.
The result shows "Pytest", not "IGNORED".
I tried many strings, also in quotes, but always get "Pytest".