I'm having a hard time trying to understand the document:
<https://docs.mongodb.com/manual/core/zone-sharding/>

As the document states: "Zones cannot share ranges, nor can they have overlapping ranges."

But still, in the example: "Shards Alpha and Beta have the A zone. Shard Beta also has the B zone"

As I understand, A zone and B zone are sharing (or overlapping) shard Alpha. Why doesn't it conflict with the mentioned rule?