Cardinality of a set that contains duplicate sets

Question

Let's assume we have a set (not a multiset), that contains three subsets

$A = \{\{a,b,b\},\{b,b,a\},\{b,a,b\}\}$

From my understanding of set theory, the three subsets are all equal to each other. So would then the cardinality of the set be one, $|A|=1 $? Thank you.

Answer 1

Yes, it's indeed just the set $\{\{a,b\}\}$.