def count$\_$unique$\_$vowels$($string$)$:

vowels $=\{\text{'}$a$\text{'},\text{'}$e$\text{'},\text{'}$i$\text{'},\text{'}$o$\text{'},\text{'}$u$\text{'}\}$

unique$\_$vowels $=$ set$()$

for char in string.lower$()$:

if char in vowels:

unique$\_$vowels.add$($char$)$

return len$($unique$\_$vowels$)$

# Test cases

print$($count$\_$unique$\_$vowels$("$swEet$"))$ # Output: $1$

print$($count$\_$unique$\_$vowels$("$AaaaeeE$"))$ # Output: $2$