Attention weights must sum to 1, but this normalizes by the count of
scores instead of their sum — so the weights come out as [0.5, 1.5]
and don't sum to 1 (the "average" is broken). Fix line 2 to divide by
the total score.
Expected output:
[0.25, 0.75]
The break is on line 2 — but read the whole snippet first.