Checking for tags efficiently

[Samuel Wales <samologist@gmail.com>]

Using org-map-entries, I check for expired done tasks and
then archive them.  I would like to skip archiving any
subtree that has the tags[1] :data: or :repurpose:.[2]

Is there a function for checking for the presence of tags
efficiently (order 1) and robustly?  Is org-entry-properties
the right thing to use?

I'm trying to avoid future debugging.

Thanks!

[1] Immediate or inherited.  I recall seeing in the code
somewhere a reference to a way to speed up the latter.

[2] In case you are curious, my plan is to use these
tags to indicate that while the tasks are done, they have
data that should be refiled or they have content that should
be repurposed.  The advantage of this over DATA and
REPURPOSE todo kw is that they can be applied orthogonally
to any todo states.  It's not ideal, because done should
mean done, but I have not found a better arrangement yet.

---
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