command_arq_raw.SendARQRawCommand isn't defined anywhere; the class is
ARQRawCommand. The always-503 busy bug hid this AttributeError, so the
endpoint can never have worked end to end.
POST /modem/send_arq_raw returned 503 Modem Busy on every request:
is_modem_busy is a threading.Event and the object is always truthy.
Use getARQ() like the beacon, message send and CQ handler do.
Note for later readers: is_set() would be inverted, since setARQ(True)
clears the event. getARQ() == True means busy.
See: https://peps.python.org/pep-0008/#imports
Here absolute imports have been used to avoid the error
`ImportError: attempted relative import with no known parent package`.
This applies mostly the same rules that `black` used.
This commit should not have introduced any logical or functional
changes, only fixing style consistency