SISMEMBER key member_value
This command is a predicate for whether or not a value is a member of a set that is associated with the given
keyis associated with a value that is not a set, an error is raised.
keydoes not exist, its associated set is empty, and the command returns 0.
memberbelongs to the given set, an integer of 1 is returned.
Returns 1 if the specified member exists. Returns 0 otherwise.
$ SADD yuga_world "America"
$ SISMEMBER yuga_world "America"
$ SISMEMBER yuga_world "Moon"