Fix “WRONGTYPE Operation against a key holding the wrong kind of value” When Calling SUNION or SUNIONSTORE in Redis

If you’re getting an error that reads “WRONGTYPE Operation against a key holding the wrong kind of value” when calling either the SUNION command or the SUNIONSTORE command in Redis, it’s probably because you’re passing a key with the wrong data type.

To fix this issue, make sure that each key that you pass holds a set.

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